feat(v2): build readthedocs (#1525)

* docs: just build readthedocs

This makes it so we don't have to disable pull request builds while we work on
v2.

* fix: add html to output dir

.readthedocs.yaml

@@ -0,0 +1,12 @@
+version: 2
+
+build:
+  os: ubuntu-22.04
+  tools:
+    python: "3.10"
+  commands:
+    - asdf plugin add uv
+    - asdf install uv latest
+    - asdf global uv latest
+    - uv sync --all-extras
+    - uv run --all-extras mkdocs build -d $READTHEDOCS_OUTPUT/html