add explicit config to rtd (pyca#12184)

also update some versions we declare, why not

Author: reaperhulk

.readthedocs.yml

@@ -6,15 +6,16 @@ sphinx:
   # The config file overrides the UI settings:
   # https://github.com/pyca/cryptography/issues/5863#issuecomment-817828152
   builder: dirhtml
+  configuration: docs/conf.py
 
 formats:
   - pdf
 
 build:
-  os: "ubuntu-22.04"
+  os: "ubuntu-24.04"
   tools:
-    python: "3.11"
-    rust: "1.70"
+    python: "3.13"
+    rust: "latest"
 
 python:
   install: