Bump actions/download-artifact from 2 to 3

Bumps [actions/download-artifact](https://github.com/actions/download-artifact) from 2 to 3.
- [Release notes](https://github.com/actions/download-artifact/releases)
- [Commits](https://github.com/actions/download-artifact/compare/v2...v3)

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

Signed-off-by: dependabot[bot] <support@github.com>

.github/workflows/openapi.yml

@@ -63,12 +63,12 @@ jobs:
       - openapi-base
     steps:
       - name: Download openapi-head
-        uses: actions/download-artifact@v2
+        uses: actions/download-artifact@v3
         with:
           name: openapi-head
           path: openapi-head
       - name: Download openapi-base
-        uses: actions/download-artifact@v2
+        uses: actions/download-artifact@v3
         with:
           name: openapi-base
           path: openapi-base