Fix epub-related failures (godotengine#8207)

* Append closing "/" to meta description tag; do not add new description tag if one already exists

* Add closing "/" to all meta tags

* Remove URL parameters from css/js paths to fix ThemeError

* Updating package versions to reflect the latest versions in the readthedocs github repo

* noop change to trigger CI workflow

* Add verbose option to "pip3 install"

* Update python version to 3.9

* Debug Iteration

* Revert CI testing changes

* Revert module upgrades and changes it required

* Update _extensions/godot_descriptions.py

---------

Co-authored-by: Max Hilbrunner <[email protected]>

Author: dylannorthrup

_extensions/godot_descriptions.py

@@ -103,10 +103,11 @@ def generate_description(app, pagename, templatename, context, doctree):
     doctree.walkabout(generator)
 
     description = (
-        '<meta name="description" content="' + generator.create_description() + '">\n'
+        '<meta name="description" content="' + generator.create_description() + '" />\n'
     )
 
-    context["metatags"] += description
+    if not '<meta name="description"' in context["metatags"]:
+        context["metatags"] += description
 
 
 def setup(app):

_templates/layout.html

@@ -6,12 +6,12 @@
 {% endblock -%}
 
 {% block extrahead -%}
-<meta name="doc_version" content="{{ version }}">
-<meta name="doc_is_latest" content="{{ godot_is_latest }}">
+<meta name="doc_version" content="{{ version }}" />
+<meta name="doc_is_latest" content="{{ godot_is_latest }}" />
 {% endblock -%}
 
 {% block linktags -%}
-  <meta name="theme-color" content="#3d8fcc">
+  <meta name="theme-color" content="#3d8fcc" />
   {% if godot_inject_language_links -%}
   {% for alternate_lang in godot_docs_supported_languages -%}
   {# Convert to ISO 639-1 format, e.g. zh_CN -> zh-cn -#}
@@ -66,7 +66,6 @@
   {% endif %}
 
   {% block body %}{% endblock %}
-</div>
 {%- if self.comments()|trim %}
   <div class="articleComments">
     {%- block comments %}{% endblock %}