Update CI pipeline

Do not use strict golint while neofs-api-go is under
development after v2.0.0 api release. Use golang-ci
for new issues as alternative.

With v2.0.0 support we support go v1.14+, therefore
it closes #35

.github/workflows/go.yml

@@ -3,13 +3,11 @@ on:
   push:
     branches:
       - master
-      - develop
     paths-ignore:
       - '*.md'
   pull_request:
     branches:
       - master
-      - develop
     paths-ignore:
       - '*.md'
 jobs:
@@ -19,7 +17,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        go: [ '1.12.x', '1.13.x', '1.14.x']
+        go: [ '1.14.x', '1.15.x' ]
     steps:
 
     - name: Setup go
@@ -47,13 +45,9 @@ jobs:
           ${{ runner.os }}-go-
 
     - name: Get dependencies
-      run: | 
-        go get -u -v golang.org/x/lint/golint
+      run: |
         go mod tidy -v
 
-    - name: Linter
-      run: golint -set_exit_status ./...
-
     - name: Tests
       run: go test -coverprofile=coverage.txt -covermode=atomic ./...
 
@@ -61,3 +55,16 @@ jobs:
       env:
         CODECOV_TOKEN: ${{ secrets.CODECOV_TOKEN }} 
       run: bash <(curl -s https://codecov.io/bash)
+
+  golangci:
+    name: lint
+    runs-on: ubuntu-latest
+    steps:
+
+      - uses: actions/checkout@v2
+
+      - name: golangci-lint
+        uses: golangci/golangci-lint-action@v2
+        with:
+          version: v1.29
+          only-new-issues: true