build(deps): update actions/setup-python action to v5 (#138)

* build(deps): update actions/setup-python action to v5

* ci: use `python-version-file` for setup python

* ci: only deploy docs on main branch

---------

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>
Co-authored-by: Josh Willox <joshwillox@gmail.com>

.github/workflows/docs.yaml

@@ -2,6 +2,8 @@ name: "Docs"
 
 on:
   push:
+    branches:
+      - "main"
     paths:
       - docs/**
       - mkdocs.yaml
@@ -20,14 +22,10 @@ jobs:
       - name: "Install poetry"
         run: pipx install poetry
 
-      - name: "Get python version"
-        id: python
-        run: echo "version=$(yq .tool.poetry.dependencies.python pyproject.toml)" >> "$GITHUB_OUTPUT"
-
       - name: "Setup Python"
-        uses: actions/setup-python@v3
+        uses: actions/setup-python@v5
         with:
-          python-version: ${{ steps.python.outputs.version }}
+          python-version-file: "pyproject.toml"
           cache: "poetry"
 
       - name: "Install dependencies"