Add linter workflow

.github/workflows/build.yml

@@ -4,9 +4,9 @@ jobs:
   test:
     strategy:
       matrix:
-        go-version: [1.11.x, 1.12.x, 1.13.x, 1.14.x]
-        platform: [ubuntu-latest, macos-latest, windows-latest]
-    runs-on: ${{ matrix.platform }}
+        go-version: [1.11.x, 1.12.x, 1.13.x, 1.14.x, 1.15.x]
+        os: [ubuntu-latest, macos-latest, windows-latest]
+    runs-on: ${{ matrix.os }}
     env:
       GO111MODULE: "on"
       COLORTERM: "truecolor"

.github/workflows/lint.yml

@@ -0,0 +1,20 @@
+name: lint
+on: [push, pull_request]
+
+jobs:
+  golangci:
+    name: lint
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+      - name: golangci-lint
+        uses: golangci/golangci-lint-action@v2
+        with:
+          # Required: the version of golangci-lint is required and must be specified without patch version: we always use the latest patch version.
+          version: v1.30
+          # Optional: golangci-lint command line arguments.
+          args: --issues-exit-code=0
+          # Optional: working directory, useful for monorepos
+          # working-directory: somedir
+          # Optional: show only new issues if it's a pull request. The default value is `false`.
+          only-new-issues: true