Update deployment info

CONTRIBUTING.rst

@@ -18,6 +18,17 @@ will automatically be deployed to Heroku. This process takes less than 5 minutes
 If after 10 minutes you did not see the changes reflected, please ping one
 of the collaborators listed below.
 
+To enable Automatic deployment:
+
+- On the Heroku dashboard for bedevere, choose the "Deploy" tab.
+- Scroll down to the "Automatic deploys" section
+- Enter the name of the branch to be deployed (in this case: ``main``)
+- Check the "Wait for CI to pass before deploy" button
+- Press the "Enable automatic deploys" button.
+
+Once done, merging a PR against the ``main`` branch will trigger a new
+deployment using a webhook that is already set up in the repo settings.
+
 
 .. note::
 
@@ -36,35 +47,25 @@ Heroku admins can do it too.
 
    Details at: https://devcenter.heroku.com/articles/heroku-cli
 
-#. Login to Heroku CLI on the command line and follow instructions
-
-   ::
+#. Login to Heroku CLI on the command line and follow instructions::
 
       heroku login
 
 
-#. If you haven't already, get a clone of the bedevere repo
-
-   ::
+#. If you haven't already, get a clone of the bedevere repo::
 
       git clone git@github.com:python/bedevere.git
 
-   Or, using `GitHub CLI`_
-
-   ::
+   Or, using `GitHub CLI`_::
 
       gh repo clone python/bedevere 
 
-#. From the ``bedevere`` directory, add the ``bedevere`` Heroku app as remote branch
-
-   ::
+#. From the ``bedevere`` directory, add the ``bedevere`` Heroku app as remote branch::
 
       heroku git:remote -a bedevere
 
 
-#. From the ``bedevere`` directory, push to Heroku
-
-   ::
+#. From the ``bedevere`` directory, push to Heroku::
 
       git push heroku main