Bump actions/upload-artifact from 5 to 6 (#667)

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

Author: dependabot[bot]

.github/workflows/part_docs.yml

@@ -42,7 +42,7 @@ jobs:
       - run: mix deps.compile
       - run: mix compile --warning-as-errors
       - run: mix docs
-      - uses: actions/upload-artifact@v5
+      - uses: actions/upload-artifact@v6
         with:
           name: docs
           path: doc

.github/workflows/part_test.yml

@@ -197,7 +197,7 @@ jobs:
           restore-keys: |
             dialyzer_plt_dev-${{ runner.os }}-${{ steps.setupBEAM.outputs.otp-version }}-${{ steps.setupBEAM.outputs.elixir-version }}-
       - run: mix dialyzer --plt
-      - uses: actions/upload-artifact@v5
+      - uses: actions/upload-artifact@v6
         with:
           name: dialyzer_plt_dev
           path: priv/plts/