Bump actions/upload-artifact from 5 to 6 (#916)

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

Author: dependabot[bot]

.github/workflows/ci.yml

@@ -180,7 +180,7 @@ jobs:
           echo '```' >> $GITHUB_STEP_SUMMARY
           exit $COV_EXIT_CODE
       - name: Upload HTML report
-        uses: actions/upload-artifact@v5
+        uses: actions/upload-artifact@v6
         with:
           name: coverage-html-report
           path: htmlcov

.github/workflows/wheel-builder.yml

@@ -83,7 +83,7 @@ jobs:
 
       - run: mkdir pynacl-wheelhouse
       - run: mv wheelhouse/pynacl*.whl pynacl-wheelhouse/
-      - uses: actions/upload-artifact@v5
+      - uses: actions/upload-artifact@v6
         with:
           name: "pynacl-${{ github.event.inputs.version }}-${{ matrix.MANYLINUX.NAME }}-${{ matrix.PYTHON.VERSION }}"
 
@@ -144,7 +144,7 @@ jobs:
 
       - run: mkdir pynacl-wheelhouse
       - run: mv wheelhouse/pynacl*.whl pynacl-wheelhouse/
-      - uses: actions/upload-artifact@v5
+      - uses: actions/upload-artifact@v6
         with:
           name: "pynacl-${{ github.event.inputs.version }}-macOS-${{ matrix.PYTHON.VERSION }}"
           path: pynacl-wheelhouse/
@@ -216,7 +216,7 @@ jobs:
           python -c "import nacl.signing; key = nacl.signing.SigningKey.generate();signature = key.sign(b'test'); key.verify_key.verify(signature)"
       - run: mkdir pynacl-wheelhouse
       - run: move wheelhouse\pynacl*.whl pynacl-wheelhouse\
-      - uses: actions/upload-artifact@v5
+      - uses: actions/upload-artifact@v6
         with:
           name: "pynacl-${{ github.event.inputs.version }}-win-${{ matrix.WINDOWS.ARCH }}-${{ matrix.PYTHON.VERSION }}"
           path: pynacl-wheelhouse\