Try to fix use of github variable.

Signed-off-by: Jelmer de Wolde <jelmer.de.wolde@alliander.com>

Author: Jelmerdw

.github/workflows/dockerfiles-changed.yml

@@ -19,9 +19,9 @@ jobs:
   deploy-docker-image:
     uses: ./.github/workflows/deploy-docker-image.yml
     with:
-      container-image: rcdt/robotics:${GITHUB_HEAD_REF/\//-}-latest
+      container-image: rcdt/robotics:${{ github.head_ref }}-latest
     secrets: inherit
   ros-workspace:
     uses: ./.github/workflows/ros-workspace.yml
     with:
-      container-image: rcdt/robotics:${GITHUB_HEAD_REF/\//-}-latest
+      container-image: rcdt/robotics:${{ github.head_ref }}-latest