- downgrade z3c.checkversions which requires pinning setuptools

Pinning setuptools causes nothing but trouble in several other projects
that I maintain that use the Zope version pins. The version pin was
required because z3c.checkversions 2.0 introduced its own setuptools version
pin, so this PR downgrades it to version 1.2 again.

constraints.txt

@@ -26,7 +26,6 @@ pycparser==2.21
 python-gettext==5.0
 pytz==2023.3
 roman==4.0
-setuptools==65.7.0
 six==1.16.0
 soupsieve==2.4.1
 transaction==3.1.0

requirements-full.txt

@@ -27,7 +27,6 @@ pycparser==2.21
 python-gettext==5.0
 pytz==2023.3
 roman==4.0
-setuptools==65.7.0
 six==1.16.0
 soupsieve==2.4.1
 transaction==3.1.0

versions-prod.cfg

@@ -31,7 +31,6 @@ python-gettext = 5.0
 pytz = 2023.3
 six = 1.16.0
 roman = 4.0
-setuptools = 65.7.0
 soupsieve = 2.4.1
 transaction = 3.1.0
 waitress = 2.1.2

versions.cfg

@@ -39,6 +39,9 @@ sphinxcontrib-qthelp = 1.0.3
 sphinxcontrib-serializinghtml = 1.1.5
 tempstorage = 6.0
 urllib3 = 2.0.2
-z3c.checkversions = 2.0
+# z3c.checkversions 2.0 pins setuptools, which then requires adding a version
+# pin for setuptools in Zope, which in turn caused issues in many projects I
+# have seen that rely on the Zope version pins.
+z3c.checkversions = 1.2
 zc.recipe.testrunner = 3.0
 zope.testrunner = 6.0