fix CI for newest github-ci branch

Author: mulle-nat

.github/workflows/mulle-sde-artifacts.yml

@@ -26,7 +26,7 @@ jobs:
 
     - uses: mulle-sde/github-ci@v2
 
-    - uses: mulle-cc/github-ci@v5
+    - uses: mulle-cc/github-ci@v6
 
     - name: Choose musl on Linux
       run: |

.github/workflows/mulle-sde-ci.yml

@@ -38,7 +38,7 @@ jobs:
 
     - uses: mulle-sde/github-ci@v2
 
-    - uses: mulle-cc/github-ci@v5
+    - uses: mulle-cc/github-ci@v6
 
     - name: Dump Project Environment
       run:  |