Add a deployment step to gh-pages branch

Following the instructions from CircleCI's blog https://circleci.com/blog/deploying-documentation-to-github-pages-with-continuous-integration/

Author: QuLogic

.circleci/config.yml

@@ -21,7 +21,37 @@ jobs:
  - store_artifacts:
  path: docs/_build/html/
 
+ deploy:
+ docker:
+ - image: "node:8.10.0"
+ steps:
+ - attach_workspace:
+ at: html
+ - run:
+ name: Install and configure dependencies
+ command: |
+ npm install -g --silent gh-pages@2.0.1
+ git config user.email "MatplotlibCircleBot@nomail"
+ git config user.name "MatplotlibCircleBot"
+ - add_ssh_keys:
+ fingerprints:
+ - "25:2e:77:93:7e:0e:af:77:b0:be:e7:fe:86:2c:5b:96"
+ - run:
+ name: "Deploy new docs"
+ command: |
+ touch html/.nojekyll # Disable jekyll builds on GitHub.
+ gh-pages \
+ --dotfiles \
+ --message "[skip ci] Doc build of $CIRCLE_SHA1" \
+ --dist html
+
 workflows:
  main:
  jobs:
  - build_docs
+ - deploy:
+ requires:
+ - build_docs
+ filters:
+ branches:
+ only: main