Fix build_docs gh action with some minor improvements (#143)

Fix `build_docs` github action that was previously broken. Some other minor improvements were added as part of this fix.

Changes include:

- `build_docs` action is triggered when we push to develop branch
    - Previously, it was on PR closed, which isn't necessarily a merge, i.e. a contributor could close a PR without merging and the action would still trigger
- Use `GITHUB_TOKEN` instead of personal authentication (PA) credentials to push
- Use "action@github.com" as the git author (user) to distinguish automated commits from human commits
- Check static files from doc branch into develop, so that we can modify
  them in a regular PR to `develop`, rather than have to edit the doc branch
  directly. I'd like for us to get to a point where doc branch pushes are fully automated, so we should never have to modify it directly.
    - Static files include: `.nojekyll` (both top-level and per-sphinx-build), `CNAME`, and top-level `index.html`


[ Committed by @ben-albrecht ]
[ Reviewed by @Spartee ]

.docs_static/CNAME

@@ -0,0 +1 @@
+www.craylabs.org

.docs_static/index.html

@@ -0,0 +1,2 @@
+
+<meta http-equiv="refresh" content="0; url=./docs/overview.html" />

.github/workflows/build_docs.yml

@@ -1,8 +1,9 @@
 name: deploy_dev_docs
 
 on:
-  pull_request:
-    types: [closed]
+  push:
+    branches:
+      - develop
 
 jobs:
   build_docs:
@@ -14,28 +15,30 @@ jobs:
         with:
           fetch-depth: 0 # otherwise, there would be errors pushing refs to the destination repository.
 
-      - name: build documentation with docker
-        run: make docks
-
       - uses: actions/checkout@v2
         with:
           ref: doc
           path: doc-branch
 
-      - name: Move over release docs and stubs
+      - name: Copy over other doc versions from doc branch
         run: |
           rm -rf doc-branch/docs/develop/
+          mkdir -p ./docs
           cp -r doc-branch/docs/* ./docs/
-          touch ./docs/.nojekyll
-          touch ./docs/develop/.nojekyll
           rm -rf doc-branch
 
-      - name: Commit files and push
+      - name: build documentation with docker
+        run: make docks
+
+      - name: Commit files
         run: |
-          git config --local user.email "spartee@hpe.com"
-          git config --local user.name "Sam Partee"
-          git checkout -b doc
-          git add .
+          git add -A
+          git config --local user.email "action@github.com"
+          git config --local user.name "GitHub Action"
           git commit -m "Update develop documentation"
-          git push --force --quiet "https://spartee:${{ secrets.DOC_PA_TOKEN }}@github.com/CrayLabs/SmartSim" doc:doc
 
+      - uses: ad-m/github-push-action@v0.6.0
+        with:
+          github_token: ${{ secrets.GITHUB_TOKEN }}
+          branch: doc
+          force: true

Makefile

@@ -93,12 +93,13 @@ docs:
 # help: docks                          - generate project documentation with docker
 .PHONY: docks
 docks:
-	@if [ -d "docs" ]; then rm -rf docs; fi
+	@rm -rf docs/develop
 	@mkdir -p docs
 	@docker compose build --progress=plain docs-dev
 	@docker create -ti --name devdocs smartsim-docs:dev-latest
-	@docker cp devdocs:/usr/local/src/SmartSim/doc/_build/html/ ./docs/develop/
+	@docker cp devdocs:/usr/local/src/SmartSim/doc/_build/html/ ./docs/develop
 	@docker container rm devdocs
+	@cp -r .docs_static/. ./docs/
 
 # help: cov                            - generate html coverage report for Python client
 .PHONY: cov