Bump actions/upload-artifact from 3 to 4 (#40)

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

.github/workflows/swift-ci.yml

@@ -35,7 +35,7 @@ jobs:
           xcodebuild test-without-building -sdk ${{ matrix.sdk }} -project ConfigCat.xcodeproj -scheme "ConfigCat" -destination "${{ matrix.destination }}" CODE_SIGNING_REQUIRED=NO -resultBundlePath tests/${{ matrix.platform }}.xcresult
       - name: Archive results
         if: failure()
-        uses: actions/upload-artifact@v3
+        uses: actions/upload-artifact@v4
         with:
           name: test-results
           path: tests
@@ -57,7 +57,7 @@ jobs:
           xcodebuild test-without-building -sdk ${{ matrix.sdk }} -project ConfigCat.xcodeproj -scheme "ConfigCat" -destination "${{ matrix.destination }}" -resultBundlePath tests/${{ matrix.platform }}.xcresult
       - name: Archive results
         if: failure()
-        uses: actions/upload-artifact@v3
+        uses: actions/upload-artifact@v4
         with:
           name: test-results
           path: tests