.github: Add concurrency handling, pre-commit, just one job

.github/workflows/push.yaml

@@ -2,26 +2,24 @@ name: Go
 
 on: [push]
 
+# This concurrency rule is not really relevant here but is nice for
+# cut-n-pasting to elsewhere
+concurrency:
+  group: ${{ github.workflow }}-${{ github.event.pull_request.number || github.ref }}
+  cancel-in-progress: true
+
 jobs:
-  lint:
+  ci:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v4
+      - uses: pre-commit/[email protected]
       - uses: actions/setup-go@v5
         with:
           go-version-file: 'go.mod'
-          cache: false
       - name: golangci-lint
         uses: golangci/golangci-lint-action@v5
         with:
           version: latest
-
-  build:
-    runs-on: ubuntu-latest
-    steps:
-      - uses: actions/checkout@v4
-      - uses: actions/setup-go@v5
-        with:
-          go-version-file: 'go.mod'
       - run: |
           make build