Roll back pyversion bump (being handled in another PR)

Author: tturocy

.github/workflows/python.yml

@@ -10,7 +10,7 @@ jobs:
     if: github.event_name != 'pull_request' || github.event.pull_request.head.repo.full_name != github.event.pull_request.base.repo.full_name
     strategy:
       matrix:
-        python-version: ['3.10', '3.14']
+        python-version: ['3.9', '3.13']
 
     steps:
       - uses: actions/checkout@v5
@@ -39,7 +39,7 @@ jobs:
     if: github.event_name != 'pull_request' || github.event.pull_request.head.repo.full_name != github.event.pull_request.base.repo.full_name
     strategy:
       matrix:
-        python-version: ['3.14']
+        python-version: ['3.13']
 
     steps:
       - uses: actions/checkout@v4
@@ -63,7 +63,7 @@ jobs:
     if: github.event_name != 'pull_request' || github.event.pull_request.head.repo.full_name != github.event.pull_request.base.repo.full_name
     strategy:
       matrix:
-        python-version: ['3.14']
+        python-version: ['3.13']
 
     steps:
       - uses: actions/checkout@v4
@@ -88,7 +88,7 @@ jobs:
     if: github.event_name != 'pull_request' || github.event.pull_request.head.repo.full_name != github.event.pull_request.base.repo.full_name
     strategy:
       matrix:
-        python-version: ['3.14']
+        python-version: ['3.13']
 
     steps:
       - uses: actions/checkout@v5

pyproject.toml

@@ -7,7 +7,7 @@ name = "pygambit"
 version = "16.4.0"
 description = "The package for computation in game theory"
 readme = "src/README.rst"
-requires-python = ">=3.10"
+requires-python = ">=3.9"
 license = "GPL-2.0-or-later"
 authors = [
     {name = "Theodore Turocy", email = "ted.turocy@gmail.com"},
@@ -17,11 +17,11 @@ keywords = ["game theory", "Nash equilibrium"]
 classifiers=[
     "Development Status :: 5 - Production/Stable",
     "Intended Audience :: Science/Research",
+    "Programming Language :: Python :: 3.9",
     "Programming Language :: Python :: 3.10",
     "Programming Language :: Python :: 3.11",
     "Programming Language :: Python :: 3.12",
     "Programming Language :: Python :: 3.13",
-    "Programming Language :: Python :: 3.14",
     "Programming Language :: Python :: Implementation :: CPython",
     "Topic :: Scientific/Engineering :: Mathematics"
 ]