chore(deps): bump actions/upload-artifact from 5 to 6

Bumps [actions/upload-artifact](https://github.com/actions/upload-artifact) from 5 to 6.
- [Release notes](https://github.com/actions/upload-artifact/releases)
- [Commits](actions/upload-artifact@v5...v6)

---
updated-dependencies:
- dependency-name: actions/upload-artifact
  dependency-version: '6'
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

Author: dependabot[bot]

.github/workflows/test.yml

@@ -114,7 +114,7 @@ jobs:
 
       - name: Upload compatibility report
         if: needs.options.outputs.mode == 'report'
-        uses: actions/upload-artifact@v5
+        uses: actions/upload-artifact@v6
         with:
           name: compat-${{ matrix.os }}-${{ matrix.toolchain.compiler }}-${{ matrix.toolchain.version }}
           path: compat/*.csv
@@ -161,7 +161,7 @@ jobs:
           cat compat.md
 
       - name: Upload artifacts
-        uses: actions/upload-artifact@v5
+        uses: actions/upload-artifact@v6
         with:
           name: compat
           path: |