gh-actions: move PR checks from static tests to own workflow

.github/workflows/check-labels.yml

@@ -1,15 +0,0 @@
-name: check-labels
-on:
-  pull_request:
-    types: [opened, reopened, labeled, unlabeled, synchronize]
-  pull_request_review:
-    types: [submitted, dismissed]
-jobs:
-  check-labels:
-    runs-on: ubuntu-latest
-    steps:
-    - uses: RIOT-OS/check-labels-action@v1.0.0
-      with:
-        access_token: ${{ secrets.GITHUB_TOKEN }}
-        unset_labels: 'CI: needs squashing,State: waiting for other PR'
-        cond_labels: '(Process: needs >1 ACK,review.approvals>1),(Area: RDM,review.approvals>2)'

.github/workflows/check-pr.yml

@@ -0,0 +1,39 @@
+name: check-pr
+on:
+  pull_request:
+    types: [opened, reopened, labeled, unlabeled, synchronize]
+  pull_request_review:
+    types: [submitted, dismissed]
+jobs:
+  check-labels:
+    runs-on: ubuntu-latest
+    steps:
+    - uses: RIOT-OS/check-labels-action@v1.0.0
+      with:
+        access_token: ${{ secrets.GITHUB_TOKEN }}
+        unset_labels: 'CI: needs squashing,State: waiting for other PR'
+        cond_labels: '(Process: needs >1 ACK,review.approvals>1),(Area: RDM,review.approvals>2)'
+  check-commits:
+    runs-on: ubuntu-latest
+    if: ${{ github.base_ref }}
+    strategy:
+      fail-fast: false
+      matrix:
+        check: [commit-msg, pr_check]
+    steps:
+    - uses: actions/checkout@master
+      with:
+        # Use the SHA of the PR branch as-is, not the PR branch merged
+        # in master (default behavior in GH actions)
+        # See https://github.com/actions/checkout#checkout-pull-request-head-commit-instead-of-merge-commit
+        ref: ${{ github.event.pull_request.head.sha }}
+        fetch-depth: 0
+    - name: Fetch base branch
+      run:
+        git fetch origin '${{ github.base_ref }}:${{ github.base_ref }}'
+    - name: Run checks
+      env:    # enforce deactivation of label check in pr_check
+        TRAVIS_PULL_REQUEST:
+        CI_PULL_NR:
+      run: |
+        ./dist/tools/${{ matrix.check }}/check.sh "${{ github.base_ref }}"

dist/tools/ci/static_tests.sh

@@ -103,7 +103,6 @@ fi
 
 export BASE_BRANCH="${CI_BASE_BRANCH}"
 
-run ./dist/tools/commit-msg/check.sh "${BASE_BRANCH}"
 run ./dist/tools/whitespacecheck/check.sh "${BASE_BRANCH}"
 DIFFFILTER="MR" ERROR_EXIT_CODE=0 run ./dist/tools/licenses/check.sh
 DIFFFILTER="AC" run ./dist/tools/licenses/check.sh
@@ -111,7 +110,6 @@ run ./dist/tools/doccheck/check.sh
 run ./dist/tools/externc/check.sh
 run ./dist/tools/cppcheck/check.sh
 run ./dist/tools/vera++/check.sh
-run ./dist/tools/pr_check/pr_check.sh "${BASE_BRANCH}"
 run ./dist/tools/coccinelle/check.sh
 run ./dist/tools/flake8/check.sh
 run ./dist/tools/headerguards/check.sh