Fix Sphinx builds (#8838)

Since Saturday the CI pipeline is failing due to several Sphinx errors. See https://dev.azure.com/certbot/certbot/_build/results?buildId=3928&view=logs&j=d74e04fe-9740-597d-e9fa-1d0400037dfd&t=dde413a4-f24c-59a0-9684-e33d79f9aa02

First, the build of certbot-dns-google is failing because of a particular configuration. It seems that this configuration has been written here to activate the support of the RST instruction `.. code-block:: json` in documentation. However, it does not seem to be necessary for a similar situation in certbot-dns-route53 documentation. So let's try to remove it and fix the Sphinx builds.

Second, Sphinx builds were not pinning dependencies, so Sphinx 4.x (that has been released yesterday) started to be used in the pipeline. Sadly this new version is not compatible with the plugin `repoze.sphinx.autointerface`, used to extract documentation from `zope.interface`. So I fixed the pinning and also explicitly pin Sphinx to 3.5.x for now.

Technically speaking the second action is sufficient to fix the first error, but I keep the dedicated solution because it improves the documentation in my opinion.

This situation could be fixed by not requiring `repoze.sphinx.autointerface`, but this is possible only if we remove `zope.interface` from Certbot. Luckily I started the work few days ago ;).

* Remove explicit lexer call in certbot-dns-google doc builds.

* Write a valid JSON file in the documentation

* Apply constraints to sphinx build environments

* Pin Sphinx to 3.5.4

* Update dependencies

* Pin traitlets

certbot-dns-google/certbot_dns_google/__init__.py

@@ -51,8 +51,16 @@ are automatically obtained by certbot through the `metadata service
    :caption: Example credentials file:
 
    {
-     "type": "service_account",
-     ...
+      "type": "service_account",
+      "project_id": "...",
+      "private_key_id": "...",
+      "private_key": "...",
+      "client_email": "...",
+      "client_id": "...",
+      "auth_uri": "https://accounts.google.com/o/oauth2/auth",
+      "token_uri": "https://accounts.google.com/o/oauth2/token",
+      "auth_provider_x509_cert_url": "https://www.googleapis.com/oauth2/v1/certs",
+      "client_x509_cert_url": "..."
    }
 
 The path to this file can be provided interactively or using the

certbot-dns-google/docs/_ext/jsonlexer.py

@@ -1,16 +0,0 @@
-"""Copied from https://stackoverflow.com/a/16863232"""
-
-def setup(app):
-    # enable Pygments json lexer
-    try:
-        import pygments
-        if pygments.__version__ >= '1.5':
-            # use JSON lexer included in recent versions of Pygments
-            from pygments.lexers import JsonLexer
-        else:
-            # use JSON lexer from pygments-json if installed
-            from pygson.json_lexer import JSONLexer as JsonLexer
-    except ImportError:
-        pass  # not fatal if we have old (or no) Pygments and no pygments-json
-    else:
-        app.add_lexer('json', JsonLexer())

certbot-dns-google/docs/conf.py

@@ -35,8 +35,7 @@ extensions = ['sphinx.ext.autodoc',
     'sphinx.ext.intersphinx',
     'sphinx.ext.todo',
     'sphinx.ext.coverage',
-    'sphinx.ext.viewcode',
-    'jsonlexer']
+    'sphinx.ext.viewcode']
 
 autodoc_member_order = 'bysource'
 autodoc_default_flags = ['show-inheritance']