Drop Python 3.9 support

NumPy and other major scientific Python packages have already dropped support in April 2024, see https://numpy.org/neps/nep-0029-deprecation_policy.html

.github/workflows/integration.yml

@@ -24,7 +24,7 @@ jobs:
     strategy:
       # Add a list of python versions we want to use for testing.
       matrix:
-        python-version: ['3.9', '3.10', '3.11', '3.12']
+        python-version: ['3.10', '3.11', '3.12']
 
     steps:
       - uses: actions/checkout@v4

.github/workflows/tests.yml

@@ -23,7 +23,7 @@ jobs:
     strategy:
       # Add a list of python versions we want to use for testing.
       matrix:
-        python-version: ['3.9', '3.10', '3.11', '3.12']
+        python-version: ['3.10', '3.11', '3.12']
 
     # Steps represent a sequence of tasks that will be executed as part of the job
     steps:

setup.py

@@ -35,7 +35,7 @@
 # See https://setuptools.readthedocs.io/en/latest/userguide/entry_point.html
 # setup_keywords['entry_points'] = {'console_scripts': ['to_snowglobes = snewpy.to_snowglobes:generate_time_series', ], },
 setup_keywords['provides'] = [setup_keywords['name']]
-setup_keywords['python_requires'] = '>=3.9'
+setup_keywords['python_requires'] = '>=3.10'
 setup_keywords['zip_safe'] = False
 setup_keywords['packages'] = find_packages('python')
 setup_keywords['package_dir'] = {'': 'python'}