chore: remove dead cookiecutter regeneration infrastructure

The repo was bootstrapped from `cookiecutter-pylibrary`. The
regeneration scaffolding has been sitting around since then — unused,
out of date, and in some cases pointing at infrastructure (AppVeyor)
that hasn't been part of CI for years. Knock it all down in one
sweep so there's nothing dead-by-design in the tree after this PR.

Removed
- `.cookiecutterrc` — cookiecutter regen metadata.
- `ci/bootstrap.py` — entry point for regenerating workflow files
  from the templates.
- `ci/templates/` (whole directory):
  - `.appveyor.yml` template (AppVeyor isn't wired up).
  - `.github/workflows/github-actions.yml` Jinja template (the live
    workflow has evolved past it via #32, #35, #37).

Coupled updates
- `tox.ini`: dropped the `[testenv:bootstrap]` env (calls deleted
  `bootstrap.py`) and the `bootstrap` reference in the basepython
  selector.
- `MANIFEST.in`: removed `include .cookiecutterrc`.
- `setup.cfg`: removed `ci/templates` from the flake8 `exclude` and
  isort `skip` lists (dead exclusion paths).
- `.pre-commit-config.yaml`: removed `ci/templates` from the
  top-level `exclude` regex.
- `tests.local.sh`: replaced the per-version `if/elif` chain (which
  still listed Python 3.7 and missed 3.12-3.14) with a single
  programmatic `tox -e py$VERSION` lookup against
  `tox --listenvs-all`. Self-maintaining when the matrix changes.
- `CHANGELOG.rst`: added a Housekeeping bullet for this PR.

Live and untouched
- `ci/requirements.txt` is still installed by every CI workflow
  (`pip install -r ci/requirements.txt`). Not regen-related.

Closes #46

1 files changed, 8 insertions, 22 deletions

diff --git a/tests.local.sh b/tests.local.sh
index 730aeee..773e279 100755
--- a/tests.local.sh
+++ b/tests.local.sh
@@ -10,30 +10,16 @@ tox -e check -v
 # Run Docs
 tox -e docs -v
 
-# Get the current installed python version
-PYTHON_VERSION=$(python3 -c 'import sys; print(".".join(map(str, sys.version_info[:3])))')
+# Run the tox env matching the current Python version
+PY_NODOT=$(python3 -c 'import sys; print("{0.major}{0.minor}".format(sys.version_info))')
+TOX_ENV="py${PY_NODOT}"
 
-# Subset the python version to the major.minor version
-PYTHON_VERSION=$(echo $PYTHON_VERSION | cut -d. -f1,2)
-
-if [ "$PYTHON_VERSION" = "3.7" ]; then
-    # Build using python 3.7
-    tox -e py37 -v
-elif [ "$PYTHON_VERSION" = "3.8" ]; then
-    # Build using python 3.8
-    tox -e py38 -v
-elif [ "$PYTHON_VERSION" = "3.9" ]; then
-    # Build using python 3.9
-    tox -e py39 -v
-elif [ "$PYTHON_VERSION" = "3.10" ]; then
-    # Build using python 3.10
-    tox -e py310 -v
-elif [ "$PYTHON_VERSION" = "3.11" ]; then
-    # Build using python 3.11
-    tox -e py311 -v
+if tox --listenvs-all | grep -qE "^${TOX_ENV}$"; then
+    tox -e "${TOX_ENV}" -v
 else
-    # Show error message
-    echo "Python version $PYTHON_VERSION is not supported"
+    PY_DOTTED=$(python3 -c 'import sys; print("{0.major}.{0.minor}".format(sys.version_info))')
+    echo "Python ${PY_DOTTED} (tox env ${TOX_ENV}) is not in tox envlist"
+    exit 1
 fi
 
 # Run Coverage