Revert min version to build book.

Author: morriscb

.github/workflows/deploy_book.yaml

@@ -17,7 +17,7 @@ jobs:
     - name: Set up Python 3.8
       uses: actions/setup-python@v2
       with:
-        python-version: 3.12
+        python-version: 3.8
 
     - name: Install dependencies
       run: |

pyproject.toml

@@ -14,7 +14,7 @@ dependencies = [
   "pydantic",
   "tqdm"
 ]
-requires-python = ">=3.9"
+requires-python = ">=3.8"
 authors = [
   {name = "Christopher Morrison", email = "[email protected]"},
 ]