Bump actions/upload-artifact from 6 to 7 (#365)

Bumps [actions/upload-artifact](https://github.com/actions/upload-artifact) from 6 to 7.
- [Release notes](https://github.com/actions/upload-artifact/releases)
- [Commits](actions/upload-artifact@v6...v7)

---
updated-dependencies:
- dependency-name: actions/upload-artifact
  dependency-version: '7'
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

.github/workflows/maven-build.yml

@@ -22,7 +22,7 @@ jobs:
       - name: Build with Maven
         run: mvn -B package
       - name: Upload artifact
-        uses: actions/upload-artifact@v6
+        uses: actions/upload-artifact@v7
         with:
           name: "BetterGUI"
           path: "./target/bettergui*.jar"

.github/workflows/maven-release.yml

@@ -27,7 +27,7 @@ jobs:
         run: mvn -B install javadoc:javadoc
 
       - name: Upload artifact
-        uses: actions/upload-artifact@v6
+        uses: actions/upload-artifact@v7
         with:
           name: "BetterGUI"
           path: |