Add golangci-lint (#310)

* Create .golangci.yml

* Create lint.yml

* Delete lint.yml

* Update test.yml

* Restore schedule

Author: 0x2b3bfa0

.github/workflows/test.yml

@@ -1,12 +1,20 @@
 name: Test
 on:
   push:
+    tags:
+      - v*
+    branches:
+      - main
   pull_request:
   schedule:
   - cron: '0 9 * * 1'  # M H d m w (Mondays at 9:00)
 jobs:
+  lint:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+      - uses: golangci/golangci-lint-action@v2
   test:
-    if: startsWith(github.ref, 'refs/tags') || github.event_name == 'pull_request' || github.event_name == 'schedule' || github.repository_owner != 'iterative'
     runs-on: ubuntu-latest
     steps:
     - uses: actions/setup-go@v2

.golangci.yml

@@ -0,0 +1,9 @@
+run:
+  timeout: 10m
+  skip-dirs:
+    - iterative
+    - cml
+output:
+  format: github-actions
+severity:
+  default-severity: error