[#128] Rename migrate methods to update

Neo Legacy used migration mechanism to update contracts.
N3 provides update method in native management contract.
Therefore, it makes sense to rename `Migrate` to `Update`.

Signed-off-by: Alex Vanin <alexey@nspcc.ru>

alphabet/alphabet_contract.go

@@ -73,9 +73,9 @@ func _deploy(data interface{}, isUpdate bool) {
 	runtime.Log(name + " contract initialized")
 }
 
-// Migrate method updates contract source code and manifest. Can be invoked
+// Update method updates contract source code and manifest. Can be invoked
 // only by contract owner.
-func Migrate(script []byte, manifest []byte, data interface{}) bool {
+func Update(script []byte, manifest []byte, data interface{}) bool {
 	ctx := storage.GetReadOnlyContext()
 
 	if !common.HasUpdateAccess(ctx) {

audit/audit_contract.go

@@ -73,9 +73,9 @@ func _deploy(data interface{}, isUpdate bool) {
 	runtime.Log("audit contract initialized")
 }
 
-// Migrate method updates contract source code and manifest. Can be invoked
+// Update method updates contract source code and manifest. Can be invoked
 // only by contract owner.
-func Migrate(script []byte, manifest []byte, data interface{}) bool {
+func Update(script []byte, manifest []byte, data interface{}) bool {
 	ctx := storage.GetReadOnlyContext()
 
 	if !common.HasUpdateAccess(ctx) {

balance/balance_contract.go

@@ -93,9 +93,9 @@ func _deploy(data interface{}, isUpdate bool) {
 	runtime.Log("balance contract initialized")
 }
 
-// Migrate method updates contract source code and manifest. Can be invoked
+// Update method updates contract source code and manifest. Can be invoked
 // only by contract owner.
-func Migrate(script []byte, manifest []byte, data interface{}) bool {
+func Update(script []byte, manifest []byte, data interface{}) bool {
 	ctx := storage.GetReadOnlyContext()
 
 	if !common.HasUpdateAccess(ctx) {

container/container_contract.go

@@ -98,9 +98,9 @@ func _deploy(data interface{}, isUpdate bool) {
 	runtime.Log("container contract initialized")
 }
 
-// Migrate method updates contract source code and manifest. Can be invoked
+// Update method updates contract source code and manifest. Can be invoked
 // only by contract owner.
-func Migrate(script []byte, manifest []byte, data interface{}) bool {
+func Update(script []byte, manifest []byte, data interface{}) bool {
 	ctx := storage.GetReadOnlyContext()
 
 	if !common.HasUpdateAccess(ctx) {

neofs/neofs_contract.go

@@ -109,9 +109,9 @@ func _deploy(data interface{}, isUpdate bool) {
 	runtime.Log("neofs: contract initialized")
 }
 
-// Migrate method updates contract source code and manifest. Can be invoked
+// Update method updates contract source code and manifest. Can be invoked
 // only by contract owner.
-func Migrate(script []byte, manifest []byte, data interface{}) bool {
+func Update(script []byte, manifest []byte, data interface{}) bool {
 	ctx := storage.GetReadOnlyContext()
 
 	if !common.HasUpdateAccess(ctx) {

neofsid/neofsid_contract.go

@@ -58,9 +58,9 @@ func _deploy(data interface{}, isUpdate bool) {
 	runtime.Log("neofsid contract initialized")
 }
 
-// Migrate method updates contract source code and manifest. Can be invoked
+// Update method updates contract source code and manifest. Can be invoked
 // only by contract owner.
-func Migrate(script []byte, manifest []byte, data interface{}) bool {
+func Update(script []byte, manifest []byte, data interface{}) bool {
 	ctx := storage.GetReadOnlyContext()
 
 	if !common.HasUpdateAccess(ctx) {

netmap/netmap_contract.go

@@ -123,9 +123,9 @@ func _deploy(data interface{}, isUpdate bool) {
 	runtime.Log("netmap contract initialized")
 }
 
-// Migrate method updates contract source code and manifest. Can be invoked
+// Update method updates contract source code and manifest. Can be invoked
 // only by contract owner.
-func Migrate(script []byte, manifest []byte, data interface{}) bool {
+func Update(script []byte, manifest []byte, data interface{}) bool {
 	ctx := storage.GetReadOnlyContext()
 
 	if !common.HasUpdateAccess(ctx) {

processing/processing_contract.go

@@ -49,9 +49,9 @@ func _deploy(data interface{}, isUpdate bool) {
 	runtime.Log("processing contract initialized")
 }
 
-// Migrate method updates contract source code and manifest. Can be invoked
+// Update method updates contract source code and manifest. Can be invoked
 // only by contract owner.
-func Migrate(script []byte, manifest []byte, data interface{}) bool {
+func Update(script []byte, manifest []byte, data interface{}) bool {
 	ctx := storage.GetReadOnlyContext()
 
 	if !common.HasUpdateAccess(ctx) {

proxy/proxy_contract.go

@@ -48,9 +48,9 @@ func _deploy(data interface{}, isUpdate bool) {
 	runtime.Log("proxy contract initialized")
 }
 
-// Migrate method updates contract source code and manifest. Can be invoked
+// Update method updates contract source code and manifest. Can be invoked
 // only by contract owner.
-func Migrate(script []byte, manifest []byte, data interface{}) bool {
+func Update(script []byte, manifest []byte, data interface{}) bool {
 	ctx := storage.GetReadOnlyContext()
 
 	if !common.HasUpdateAccess(ctx) {

reputation/reputation_contract.go

@@ -42,9 +42,9 @@ func _deploy(data interface{}, isUpdate bool) {
 	runtime.Log("reputation contract initialized")
 }
 
-// Migrate method updates contract source code and manifest. Can be invoked
+// Update method updates contract source code and manifest. Can be invoked
 // only by contract owner.
-func Migrate(script []byte, manifest []byte, data interface{}) bool {
+func Update(script []byte, manifest []byte, data interface{}) bool {
 	ctx := storage.GetReadOnlyContext()
 
 	if !common.HasUpdateAccess(ctx) {