Add Java automation

Fetch Java versions with their dates from https://www.java.com/releases/.

This script is using a new dependency: requests-html (https://requests-html.kennethreitz.org/). This is because https://www.java.com/releases/ needs JavaScript to render correctly. And for this to work requests-html automatically downloads Chromium because of its dependency to pyppeteer.

Chromium is downloaded into PYPPETEER_HOME, so the workflow has been modified to set this directory as a subdirectory of ~/.cache. Note that declaring the same environment variable from the python script does not work.

.github/workflows/update.yml

@@ -58,6 +58,11 @@ jobs:
         git config --global extensions.partialClone true
         pip install -r requirements.txt
     - name: Custom Updates
+      env:
+        # Add chromium downloaded by pyppeteer to the cache. See java.py for more information.
+        # Note that using we had to use /home/runner because using ~ does not work, despite what's
+        # explained in the https://github.com/actions/upload-artifact/tree/v2-preview#environment-variables-and-tilde-expansion.
+        PYPPETEER_HOME: /home/runner/.cache/pyppeteer
       run: for i in src/*.py; do python $i;done
     - name: Git and DockerHub Updates
       run: bundle exec ruby update.rb ./website ~/.cache releases