Add a golangci-lint Github Action

The go vet is appended, because I have seen some important
lint issues that are disabled by golangci-lint being reported by
the vanilla go vet commnand

.github/workflows/lint.yml

@@ -0,0 +1,14 @@
+name: lint
+on: [push]
+jobs:
+  golangci:
+    name: lint
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+      - uses: golangci/golangci-lint-action@v2
+        with:
+          version: v1.34.1
+      - name: Run go vet
+        run: |
+          go vet ./...