Use foldable helpers where applicable

As discussed at some earlier point in time, some of the actions/workflow
logic does not use our foldable helpers despite being able to. Switch
them over.

Signed-off-by: Daniel Müller <deso@posteo.net>

.github/workflows/coverity.yml

@@ -15,12 +15,13 @@ jobs:
       - uses: ./.github/actions/setup
       - name: Run coverity
         run: |
-          echo ::group::Setup CI env
+          source $GITHUB_ACTION_PATH/../../../ci/vmtest/helpers.sh
+          foldable start "Setup CI env"
           source /tmp/ci_setup
           export COVERITY_SCAN_NOTIFICATION_EMAIL="${AUTHOR_EMAIL}"
           export COVERITY_SCAN_BRANCH_PATTERN=${GITHUB_REF##refs/*/}
           export TRAVIS_BRANCH=${COVERITY_SCAN_BRANCH_PATTERN}
-          echo ::endgroup::
+          foldable end
           scripts/coverity.sh
         env:
           COVERITY_SCAN_TOKEN: ${{ secrets.COVERITY_SCAN_TOKEN }}