Pin the theme to a commit (#11472)

We are about to make a new alpha/beta release of the theme.
Until then, we will be pinning to the commit because the branch was deleted.

.readthedocs.yml

@@ -34,10 +34,10 @@ build:
         fi
 
     # Install our Sphinx Theme version that uses the Addons CustomEvent to generate the integrated flyout
-    # TODO: this custom installation once a new release has been done
+    # TODO: remove this custom installation once a new release has been done
     post_install:
       - pip uninstall --yes sphinx-rtd-theme
-      - pip install git+https://github.com/readthedocs/sphinx_rtd_theme.git@humitos/addons-flyout#egg=sphinx-rtd-theme
+      - pip install git+https://github.com/readthedocs/sphinx_rtd_theme.git@357e76dc42a89c1c387cafd8cb134378a57e4d6d#egg=sphinx-rtd-theme
 
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