drop support for Go 1.12

It's old and not maintained. Use latest Go for builds and test only with 1.13
and 1.14.

.circleci/config.yml

@@ -3,11 +3,6 @@ orbs:
   codecov: codecov/codecov@1.0.5
 
 executors:
-  go1_12:
-    docker:
-      - image: circleci/golang:1.12
-        environment:
-          GO111MODULE: "on"
   go1_13:
     docker:
       - image: circleci/golang:1.13
@@ -54,16 +49,6 @@ jobs:
           name: go-vet
           command: go vet ./...
 
-  test_1_12:
-    working_directory: /go/src/github.com/nspcc-dev/neo-go
-    executor: go1_12
-    steps:
-      - checkout
-      - run: git submodule sync
-      - run: git submodule update --init
-      - gomod
-      - run: go test -v -race ./...
-
   test_1_13:
     working_directory: /go/src/github.com/nspcc-dev/neo-go
     executor: go1_13
@@ -100,7 +85,7 @@ jobs:
 
   build_cli:
     working_directory: /go/src/github.com/nspcc-dev/neo-go
-    executor: go1_12
+    executor: go1_14
     steps:
       - checkout
       - gomod
@@ -111,7 +96,7 @@ jobs:
 
   build_image:
     working_directory: /go/src/github.com/nspcc-dev/neo-go
-    executor: go1_12
+    executor: go1_14
     docker:
       - image: golang:1-alpine
     steps:
@@ -142,10 +127,6 @@ workflows:
           filters:
             tags:
               only: v/[0-9]+\.[0-9]+\.[0-9]+/
-      - test_1_12:
-          filters:
-            tags:
-              only: v/[0-9]+\.[0-9]+\.[0-9]+/
       - test_1_13:
           filters:
             tags:

.travis.yml

@@ -1,6 +1,6 @@
 language: go
 go:
-  - 1.12.x
+  - 1.14.x
 env:
   - GO111MODULE=on
 install:

README.md

@@ -36,7 +36,7 @@ Neo 3 code (0.90.0 being compatible with Neo 3 preview2).
 
 ## Installation
 
-Go: 1.12+
+Go: 1.13+
 
 Install dependencies.
 

go.mod

@@ -28,4 +28,4 @@ require (
 	gopkg.in/abiosoft/ishell.v2 v2.0.0
 )
 
-go 1.12
+go 1.13