Bump actions/upload-pages-artifact from 1 to 2 (#29)

Bumps [actions/upload-pages-artifact](https://github.com/actions/upload-pages-artifact) from 1 to 2.
- [Release notes](https://github.com/actions/upload-pages-artifact/releases)
- [Commits](actions/upload-pages-artifact@v1...v2)

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

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

.github/workflows/build_and_test.yml

@@ -137,7 +137,7 @@ jobs:
         mkdir extensions
         ./build-docs -d ${GITHUB_WORKSPACE}/.github/workflows/docs/extensions/api
     - name: Upload docs as artefact
-      uses: actions/upload-pages-artifact@v1
+      uses: actions/upload-pages-artifact@v2
       with:
         path: .github/workflows/docs/extensions