ci: enable extra linters for new code

.github/workflows/validate.yml

@@ -23,6 +23,26 @@ jobs:
           # must be specified without patch version
           version: v1.42
 
+  lint-extra:
+    # Extra linters, only checking new code from pull requests.
+    if: github.event_name == 'pull_request'
+    runs-on: ubuntu-20.04
+    permissions:
+      contents: read
+    steps:
+      - uses: actions/checkout@v2
+      - name: install deps
+        run: |
+          sudo apt -q update
+          sudo apt -q install libseccomp-dev
+      - uses: golangci/golangci-lint-action@v2
+        with:
+          only-new-issues: true
+          args: --config .golangci-extra.yml
+          # must be specified without patch version
+          version: v1.43
+
+
   compile-buildtags:
     runs-on: ubuntu-20.04
     env:

.golangci-extra.yml

@@ -0,0 +1,15 @@
+# This is golangci-lint config file which is used to check new code in
+# github PRs only (see lint-extra job in .github/workflows/validate.yml).
+#
+# For the default linter config, see .golangci.yml. This config should
+# only enable additional linters not enabled in the default config.
+
+run:
+  build-tags:
+    - seccomp
+
+linters:
+  disable-all: true
+  enable:
+    - godot
+    - revive