Bump actions/upload-artifact from 3 to 4

Bumps [actions/upload-artifact](https://github.com/actions/upload-artifact) from 3 to 4.
- [Release notes](https://github.com/actions/upload-artifact/releases)
- [Commits](actions/upload-artifact@v3...v4)

---
updated-dependencies:
- dependency-name: actions/upload-artifact
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <[email protected]>

.github/workflows/ci.yml

@@ -40,7 +40,7 @@ jobs:
         run: grep -oP '^ARG YOURLS_VERSION="\K[^"]+' ./images/yourls/Dockerfile.template > ./images/yourls/dist/yourls_version
 
       - name: Save files
-        uses: actions/upload-artifact@v3
+        uses: actions/upload-artifact@v4
         with:
           name: context-files
           path: ./images/yourls/dist
@@ -75,7 +75,7 @@ jobs:
           cache-to: type=gha,scope=${{ matrix.variant }},mode=max
 
       - name: Save image
-        uses: actions/upload-artifact@v3
+        uses: actions/upload-artifact@v4
         with:
           name: ${{ matrix.variant }}-image
           path: /tmp/container-image.tar

.github/workflows/hub.yml

@@ -26,7 +26,7 @@ jobs:
       - name: Generate stackbrew
         run: bash ./bin/generate-stackbrew-library.sh > yourls
 
-      - uses: actions/upload-artifact@v3
+      - uses: actions/upload-artifact@v4
         with:
           name: stackbrew
           path: yourls