Pin setuptools<81 — version 82 removed pkg_resources

Pyramid 2.0.2 imports pkg_resources which was dropped from setuptools 81+.
Pin to <81 until Pyramid removes its pkg_resources dependency.

Makefile

@@ -124,7 +124,7 @@ install: install-core install-dev
 # Install from source (editable mode) for development and testing.
 install-source-dev-and-test: venv
 	@echo "Ensuring setuptools is installed (required by Pyramid on Python 3.12+)..."
-	$(PIP) install setuptools
+	$(PIP) install 'setuptools<81'
 	@echo "Installing make_post_sell from source (editable mode) for development..."
 	$(PIP) install --editable .
 	$(PIP) install --upgrade -r requirements-dev.txt
@@ -133,7 +133,7 @@ install-source-dev-and-test: venv
 # Install from source for production (non‑editable).
 install-source-prod: venv
 	@echo "Ensuring setuptools is installed (required by Pyramid on Python 3.12+)..."
-	$(PIP) install setuptools
+	$(PIP) install 'setuptools<81'
 	@echo "Deleting tests from source code for production..."
 	rm -rf make_post_sell/tests
 	@echo "Installing make_post_sell from source for production (non‑editable)..."

requirements-dev.txt

@@ -1,6 +1,6 @@
 # Python 3.12+ no longer bundles setuptools in venvs.
-# Pyramid imports pkg_resources which lives in setuptools.
-setuptools
+# Pyramid imports pkg_resources which was removed in setuptools 81+.
+setuptools<81
 
 # bpython shell and teach pyramid about it.
 bpython

requirements.py3.txt

@@ -2,8 +2,8 @@
 six
 
 # Python 3.12+ no longer bundles setuptools in venvs.
-# Pyramid imports pkg_resources which lives in setuptools.
-setuptools
+# Pyramid imports pkg_resources which was removed in setuptools 81+.
+setuptools<81
 
 # Pyramid with SQLAlchemy.
 plaster_pastedeploy