separate build and publish doc scripts (pytorch#666)

Summary:

# Context
Publish docs part of the script is failing since the directory generated by the build script isn't shared to the publish one
 {F1238220367} 

# This Diff
Creates a separate script for building and publishing the static docs. Building is only run on pull requests, build + publishing script is run on commit / land.

Differential Revision: D52525534

.github/workflows/build_and_publish_docs.yaml

@@ -0,0 +1,48 @@
+name: Build and Update Docs
+
+on:
+  push:
+    branches: [ master ]
+
+# Allow one concurrent deployment
+concurrency:
+  group: "pages"
+  cancel-in-progress: true
+
+jobs:
+  build_docs:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Check out repo
+        uses: actions/checkout@v2
+      - name: Setup conda env
+        uses: conda-incubator/setup-miniconda@v2
+        with:
+          miniconda-version: "latest"
+          activate-environment: test
+      - name: Install dependencies
+        shell: bash -l {0}
+        run: |
+          set -eux
+          conda activate test
+          pip install -r requirements.txt
+          pip install -r dev-requirements.txt
+          conda install pytorch cpuonly -c pytorch-nightly
+          python setup.py sdist bdist_wheel
+          pip install dist/*.whl
+      - name: Build docs
+        shell: bash -l {0}
+        run: |
+          set -eux
+          conda activate test
+          cd docs
+          pip install -r requirements.txt
+          make html
+          touch build/html/.nojekyll
+          cd ..
+      - name: Deploy docs to Github pages
+        uses: JamesIves/github-pages-deploy-action@v4.4.1
+        with:
+            branch: gh-pages # The branch the action should deploy to.
+            folder: docs/build/html # The folder the action should deploy.
+            target-folder: master

.github/workflows/build_docs.yaml

@@ -1,8 +1,6 @@
-name: Build and Update Docs
+name: Build Docs
 
 on:
-  push:
-    branches: [ master ]
   pull_request:
 
 # Allow one concurrent deployment
@@ -41,13 +39,3 @@ jobs:
           make html
           touch build/html/.nojekyll
           cd ..
-  publish_docs:
-    runs-on: ubuntu-latest
-    if: ${{ github.event_name == 'push' }}
-    steps:
-      - name: Deploy docs to Github pages
-        uses: JamesIves/github-pages-deploy-action@v4.4.1
-        with:
-            branch: gh-pages # The branch the action should deploy to.
-            folder: docs/build/html # The folder the action should deploy.
-            target-folder: master