found the error in the custom action

.forgejo/actions/artifact-upload/action.yml

@@ -11,6 +11,8 @@ runs:
   using: composite
   steps:
     - name: collect
-      run: true
+      shell: sh
+      run: "true"
     - name: upload
-      run: true
+      shell: sh
+      run: "true"

.forgejo/workflows/container-build.yml

@@ -13,8 +13,8 @@ jobs:
     steps:
       - run: kc.sh build
         working-directory: /opt/keycloak/
-      #- id: local-upload
-      #  uses: ./.forgejo/actions/artifact-upload
-      #  with:
-      #    name: keycloak.tar
-      #    path: /opt/keycloak
+      - id: local-upload
+        uses: ./.forgejo/actions/artifact-upload
+        with:
+          name: keycloak.tar
+          path: /opt/keycloak