ci(.github/workflows/{build,dependent-issues}.yml): auto-cancel workf…

…lows on previous commits (#7536)

After this is merged, pushing a new commit to a branch in this repo should cancel the "continuous integration" and "dependent issues" workflows running on any older commits on that branch.

.github/workflows/build.yml

@@ -12,6 +12,16 @@ on:
       - 'lean-3.*'
 
 jobs:
+  cancel:
+    name: 'Cancel Previous Runs (CI)'
+    runs-on: ubuntu-latest
+    # timeout-minutes: 3
+    steps:
+      - uses: styfle/cancel-workflow-action@0.9.0
+        with:
+          all_but_latest: true
+          access_token: ${{ github.token }}
+
   lint_self_test:
     name: Ensure the linter works
     runs-on: ${{ matrix.os }}

.github/workflows/dependent-issues.yml

@@ -16,6 +16,16 @@ on:
     - cron: '15 * * * *' # schedule hourly check for external dependencies
 
 jobs:
+  cancel:
+    name: 'Cancel Previous Runs (dependent issues)'
+    runs-on: ubuntu-latest
+    # timeout-minutes: 3
+    steps:
+      - uses: styfle/cancel-workflow-action@0.9.0
+        with:
+          all_but_latest: true
+          access_token: ${{ github.token }}
+
   check:
     runs-on: ubuntu-latest
     steps: