Relax Python version requirement from 3.13 to >=3.12 and update test matrix

Co-authored-by: mmcky <[email protected]>

Author: Copilot

.github/workflows/tests.yml

@@ -22,7 +22,7 @@ jobs:
       fail-fast: false
       matrix:
         os: [ubuntu-latest]
-        python-version: ["3.13"]
+        python-version: ["3.12", "3.13"]
         # Only test the latest major release of Sphinx because otherwise we need to
         # keep multiple versions of regression tests on file and this creates lots of
         # noise in the tests.
@@ -48,7 +48,7 @@ jobs:
         pytest --durations=10 --cov=quantecon_book_theme --cov-report=xml --cov-report=term-missing
 
     - name: Upload to Codecov
-      if: matrix.os == 'ubuntu-latest' && matrix.python-version == 3.13 && github.repository == 'QuantEcon/quantecon-book-theme' && github.event_name == 'pull_request'
+      if: matrix.os == 'ubuntu-latest' && matrix.python-version == '3.13' && github.repository == 'QuantEcon/quantecon-book-theme' && github.event_name == 'pull_request'
       uses: codecov/[email protected]
       with:
         name: ebp-qbt-pytests-py3.13

pyproject.toml

@@ -20,7 +20,7 @@ description = "A clean book theme for scientific explanations and documentation
 dynamic = ["version"]
 readme = "README.md"
 
-requires-python = ">=3.13"
+requires-python = ">=3.12"
 dependencies = [
   "pyyaml",
   "sphinx>=7,<9",

tox.ini

@@ -11,13 +11,13 @@
 # then then deleting compiled files has been found to fix it: `find . -name \*.pyc -delete`
 
 [tox]
-envlist = py313-sphinx7
+envlist = py{312,313}-sphinx7
 
 [testenv]
 usedevelop=true
 passenv = TERM  # To make terminal coloring / other variables pass through
 
-[testenv:py{313}-pre-commit]
+[testenv:py{312,313}-pre-commit]
 extras = code_style
 commands = pre-commit run {posargs}
 
@@ -43,9 +43,9 @@ deps =
 commands =
     stb serve docs --open-browser
 
-[testenv:py{313}-sphinx{7,8}]
+[testenv:py{312,313}-sphinx{7,8}]
 extras = test
 deps =
     sphinx7: sphinx>=7,<8
-    sphinx7: sphinx>=8,<9
+    sphinx8: sphinx>=8,<9
 commands = pytest {posargs}