More work on fixing CI issues

MacOS builds for building Python wheels started to complain when running
the "delocate" step that libquadmath, libstdc++, and libgfortran have
minimum targets of 11.0, whereas the default was 10.9

pyproject.toml

@@ -52,3 +52,6 @@ skip = [
   # As such we can compile but we cannot test, so we skip those.
   "cp31*-manylinux_i686",
 ]
+
+[tool.cibuildwheel.macos.environment]
+MACOSX_DEPLOYMENT_TARGET = "11"