fix(docs): Fix readthedocs build failures (#2046)

fix(docs): Use new readthedocs config

References:
- urllib3/urllib3#2168
- readthedocs/readthedocs.org#10290
- https://docs.readthedocs.io/en/stable/config-file/v2.html#legacy-build-specification

Signed-off-by: BobDotCom <[email protected]>

Author: BobDotCom

.readthedocs.yml

@@ -2,15 +2,16 @@ version: 2
 formats: []
 
 build:
-  image: latest
+  os: ubuntu-22.04
+  tools:
+    python: "3.8"
 
 sphinx:
   configuration: docs/conf.py
   fail_on_warning: false
   builder: html
 
 python:
-  version: "3.8"
   install:
     - method: pip
       path: .