Revert "pin python version for doc building"

This reverts commit 645cb6c.

Author: jepler

.github/workflows/build.yml

@@ -220,7 +220,7 @@ jobs:
     - name: Set up Python 3
       uses: actions/setup-python@v2
       with:
-        python-version: "3.10.6"
+        python-version: "3.x"
     - name: Install dependencies
       run: |
         sudo apt-get update