Drop Python 3.9 from GitHub testing

.github/workflows/build_and_test.yml

@@ -1,4 +1,4 @@
-name: Build Package and Test Source Code [Python 3.9, 3.10, 3.11, 3.12]
+name: Build Package and Test Source Code [Python 3.10, 3.11, 3.12]
 
 on: [push, pull_request]
 
@@ -8,7 +8,7 @@ jobs:
     strategy:
       matrix:
         os: [ubuntu-latest, windows-latest]
-        python-version: [3.9, '3.10', '3.11', '3.12']
+        python-version: ['3.10', '3.11', '3.12']
 
     steps:
       - name: Checkout

.github/workflows/check_jupyterbook.yml

@@ -26,4 +26,4 @@ jobs:
           pip install -e .
           python docs/guide/make/make_uguide.py
           cd docs
-          jb build .
+          jb build .

README.md

@@ -1,7 +1,7 @@
 | | |
 | --- | --- |
 | Org | [![PSL cataloged](https://img.shields.io/badge/PSL-cataloged-a0a0a0.svg)](https://www.PSLmodels.org) [![OS License: CCO-1.0](https://img.shields.io/badge/OS%20License-CCO%201.0-yellow)](https://github.com/PSLmodels/Tax-Calculator/blob/master/LICENSE) [![Jupyter Book Badge](https://jupyterbook.org/badge.svg)](https://pslmodels.github.io/Tax-Calculator/) |
-| Package | [![Python 3.9](https://img.shields.io/badge/python-3.9-blue.svg)](https://www.python.org/downloads/release/python-3916/) [![Python 3.10](https://img.shields.io/badge/python-3.10-blue.svg)](https://www.python.org/downloads/release/python-3108/)  [![Python 3.11](https://img.shields.io/badge/python-3.11-blue.svg)](https://www.python.org/downloads/release/python-3118/) [![Python 3.12](https://img.shields.io/badge/python-3.12-blue.svg)](https://www.python.org/downloads/release/python-3121/) [![PyPI Latest Release](https://img.shields.io/pypi/v/taxcalc.svg)](https://pypi.org/project/taxcalc/) [![PyPI Downloads](https://img.shields.io/pypi/dm/taxcalc.svg?label=PyPI%20downloads)](https://pypi.org/project/taxcalc/) [![Anaconda](https://img.shields.io/conda/dn/conda-forge/taxcalc?color=brightgreen&label=downloads&logo=conda-forge)](https://anaconda.org/conda-forge/taxcalc)|
+| Package | [![Python 3.10](https://img.shields.io/badge/python-3.10-blue.svg)](https://www.python.org/downloads/release/python-3108/)  [![Python 3.11](https://img.shields.io/badge/python-3.11-blue.svg)](https://www.python.org/downloads/release/python-3118/) [![Python 3.12](https://img.shields.io/badge/python-3.12-blue.svg)](https://www.python.org/downloads/release/python-3121/) [![PyPI Latest Release](https://img.shields.io/pypi/v/taxcalc.svg)](https://pypi.org/project/taxcalc/) [![PyPI Downloads](https://img.shields.io/pypi/dm/taxcalc.svg?label=PyPI%20downloads)](https://pypi.org/project/taxcalc/) [![Anaconda](https://img.shields.io/conda/dn/conda-forge/taxcalc?color=brightgreen&label=downloads&logo=conda-forge)](https://anaconda.org/conda-forge/taxcalc)|
 | Testing | ![example event parameter](https://github.com/PSLmodels/Tax-Calculator/actions/workflows/build_and_test.yml/badge.svg?branch=master) ![example event parameter](https://github.com/PSLmodels/Tax-Calculator/actions/workflows/deploy_jupyterbook.yml/badge.svg?branch=master)  [![Codecov](https://codecov.io/gh/PSLmodels/Tax-Calculator/branch/master/graph/badge.svg)](https://codecov.io/gh/PSLmodels/Tax-Calculator) |