build(deps): 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] <support@github.com>

.github/workflows/publish-appimage.yml

@@ -68,17 +68,17 @@ jobs:
       - name: Build AppImage
         run: CC=clang-14 CXX=clang++-14 ./appimage/build.sh
       - name: Upload AppImage artifact
-        uses: actions/upload-artifact@v3
+        uses: actions/upload-artifact@v4
         with:
           name: conky-x86_64.AppImage
           path: conky-x86_64.AppImage
       - name: Upload AppImage checksum artifact
-        uses: actions/upload-artifact@v3
+        uses: actions/upload-artifact@v4
         with:
           name: conky-x86_64.AppImage.sha256
           path: conky-x86_64.AppImage.sha256
       - name: Upload man page artifact
-        uses: actions/upload-artifact@v3
+        uses: actions/upload-artifact@v4
         with:
           name: conky.1.gz
           path: conky.1.gz