Upload docs artifact for PRs (#2868)

.github/workflows/docs-pr-netlify.yaml

@@ -0,0 +1,34 @@
+name: Deploy documentation PR preview
+
+on:
+  workflow_run:
+    workflows: [ "Static Analysis" ]
+    types:
+      - completed
+
+jobs:
+  netlify:
+    if: github.event.workflow_run.conclusion == 'success' && github.event.workflow_run.event == 'pull_request'
+    runs-on: ubuntu-latest
+    steps:
+      # There's a 'download artifact' action, but it hasn't been updated for the workflow_run action
+      # (https://github.com/actions/download-artifact/issues/60) so instead we get this mess:
+      - name: 📥 Download artifact
+        uses: dawidd6/action-download-artifact@b12b127cf24433d14b4f93cee62f5465076ba82a # v2.24.1
+        with:
+          workflow: static_analysis.yml
+          run_id: ${{ github.event.workflow_run.id }}
+          name: docs
+          path: docs
+
+      - name: 📤 Deploy to Netlify
+        uses: matrix-org/netlify-pr-preview@v1
+        with:
+          path: docs
+          owner: ${{ github.event.workflow_run.head_repository.owner.login }}
+          branch: ${{ github.event.workflow_run.head_branch }}
+          revision: ${{ github.event.workflow_run.head_sha }}
+          token: ${{ secrets.NETLIFY_AUTH_TOKEN }}
+          site_id: ${{ secrets.NETLIFY_SITE_ID }}
+          desc: Documentation preview
+          deployment_env: PR Documentation Preview

.github/workflows/static_analysis.yml

@@ -63,4 +63,12 @@ jobs:
         run: "yarn install"
 
       - name: Generate Docs
-        run: "yarn run gendoc"
+        run: "yarn run gendoc -d _docs"
+        
+      - name: Upload Artifact
+        uses: actions/upload-artifact@v2
+        with:
+          name: docs
+          path: _docs
+          # We'll only use this in a workflow_run, then we're done with it
+          retention-days: 1