ci: skip build-multi-stage workflow for draft PRs

Add condition to prevent the multi-arch-build job from running on draft
pull requests, saving CI resources during PR preparation.

Assisted-by: AskBob <askbob@ibm.com>
Signed-off-by: Niels de Vos <ndevos@ibm.com>

Author: nixpanic

.github/workflows/build-multi-stage.yaml

@@ -18,6 +18,7 @@ jobs:
   codespell:
     name: multi-arch-build
     runs-on: ubuntu-latest
+    if: github.event.pull_request.draft == false
     steps:
       - name: delay a minute to have labels added
         run: sleep 1m