ci: pass GITHUB_BASE_REF when running commitlint

GitHub Actions include a merge commit for the PR, which will defeat the
commitlint checking of all the commits inside the PR (only the merge
commit is checked).

Signed-off-by: Niels de Vos <ndevos@redhat.com>

.github/workflows/commitlint.yaml

@@ -11,5 +11,8 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v2
+        with:
+          ref: ${{ github.event.pull_request.head.sha }}
       - name: commitlint
-        run: CONTAINER_CMD=docker make containerized-test TARGET=commitlint
+        # yamllint disable-line rule:line-length
+        run: make containerized-test CONTAINER_CMD=docker TARGET=commitlint GIT_SINCE="origin/${GITHUB_BASE_REF}"

Makefile

@@ -148,7 +148,7 @@ commitlint: REBASE ?= 0
 commitlint:
 	git fetch -v $(shell cut -d/ -f1 <<< "$(GIT_SINCE)") $(shell cut -d/ -f2- <<< "$(GIT_SINCE)")
 	@test $(REBASE) -eq 0 || git -c user.name=commitlint -c user.email=commitline@localhost rebase FETCH_HEAD
-	commitlint --from FETCH_HEAD
+	commitlint --verbose --from $(GIT_SINCE)
 
 .PHONY: cephcsi
 cephcsi: check-env