revert: update (upload,download)-artifact to v4

~reverts commit 399b8d3. (the action was moved later).
This downgrades the action again to v3.
The download action seems to run into a timeout sometimes.
This was better with v4.

.github/workflows/reusable-e2e-tests-build.yml

@@ -45,7 +45,7 @@ jobs:
           cache-to: type=gha,scope=caddy,mode=max
           outputs: type=docker,dest=/tmp/ecamp3-dev-api-caddy.tar
 
-      - uses: actions/upload-artifact@v4
+      - uses: actions/upload-artifact@v3
         with:
           name: e2e-tests-images
           path: /tmp/ecamp3-dev-*.tar

.github/workflows/reusable-e2e-tests-run.yml

@@ -29,7 +29,7 @@ jobs:
         uses: docker/setup-buildx-action@v3
 
       - name: Restore tmp folder
-        uses: actions/download-artifact@v4
+        uses: actions/download-artifact@v3
         with:
           name: e2e-tests-images
           path: /tmp
@@ -59,7 +59,7 @@ jobs:
           wait-on-timeout: 300
 
       # store screenshots and videos on GitHub as artifacts, for downloading and debugging in case of problems
-      - uses: actions/upload-artifact@v4
+      - uses: actions/upload-artifact@v3
         if: always()
         with:
           name: cypress-output-${{ matrix.browser }}${{ inputs.run-identifier != null && format('-{0}', inputs.run-identifier) }}