[#343] client: Accept context parameter in Dial

In previous implementation of `Client.Dial` there was no ability to
specify parent context (e.g. global application context).

Add `PrmDial.SetContext` method which accepts optional base dial
context. Use the context to open client connection or fall back to using
`context.Background()`.

Upgraded version of `github.com/nspcc-dev/neofs-api-go/v2` module
also fixes the problem when dial timeout didn't work properly.

Signed-off-by: Leonard Lyubich <ctulhurider@gmail.com>

client/client_test.go

@@ -1,6 +1,7 @@
 package client
 
 import (
+	"context"
 	"crypto/ecdsa"
 	"crypto/elliptic"
 	"crypto/rand"
@@ -37,3 +38,31 @@ func newClient(server neoFSAPIServer) *Client {
 
 	return &c
 }
+
+func TestClient_DialContext(t *testing.T) {
+	var c Client
+
+	// try to connect to any host
+	var prm PrmDial
+	prm.SetServerURI("localhost:8080")
+
+	assert := func(ctx context.Context, errExpected error) {
+		// use the particular context
+		prm.SetContext(ctx)
+
+		// expect particular context error according to Dial docs
+		require.ErrorIs(t, c.Dial(prm), errExpected)
+	}
+
+	// create pre-abandoned context
+	ctx, cancel := context.WithCancel(context.Background())
+	cancel()
+
+	assert(ctx, context.Canceled)
+
+	// create "pre-deadlined" context
+	ctx, cancel = context.WithTimeout(context.Background(), 0)
+	defer cancel()
+
+	assert(ctx, context.DeadlineExceeded)
+}