MNT: Update feedstock recipe for modern noarch python

* Use 'python {{ python_min }}' syntax for the python requirements for noarch
  python recipes.
   - c.f. https://conda-forge.org/docs/maintainer/knowledge_base/#noarch-python
* Use a Jinja2 set statement for the python_min to allow all the build
  metadata to be contained in the recipe/meta.yaml and override the global
  python_min with packaging's python_min of 3.8.
* Build with '--no-deps --no-build-isolation' to verify build requirements are
  specified.
* Use 'pypi.org'.
* Add matthewfeickert and ofek as feedstock maintainers.
* Bump build number.

recipe/meta.yaml

@@ -1,29 +1,31 @@
+{% set name = "packaging" %}
 {% set version = "24.2" %}
+{% set python_min = "3.8" %}
 
 package:
-  name: packaging
+  name: {{ name|lower }}
   version: {{ version }}
 
 source:
-  url: https://pypi.io/packages/source/p/packaging/packaging-{{ version }}.tar.gz
+  url: https://pypi.org/packages/source/p/packaging/packaging-{{ version }}.tar.gz
   sha256: c228a6dc5e932d346bc5739379109d49e8853dd8223571c7c5b55260edc0b97f
 
 build:
-  number: 0
+  number: 1
   noarch: python
-  script: {{ PYTHON }} -m pip install . --no-deps -vv
+  script: {{ PYTHON }} -m pip install . -vv --no-deps --no-build-isolation
 
 requirements:
   host:
-    - python >=3.8
+    - python {{ python_min }}
     - flit >=3.3
     - pip
-
   run:
-    - python >=3.8
+    - python >={{ python_min }}
 
 test:
   requires:
+    - python {{ python_min }}
     - pip
   imports:
     - packaging
@@ -35,8 +37,12 @@ about:
   license: Apache-2.0
   license_file: LICENSE
   summary: Core utilities for Python packages
+  doc_url: https://packaging.pypa.io/
+  dev_url: https://github.com/pypa/packaging
 
 extra:
   recipe-maintainers:
     - jakirkham
     - nicoddemus
+    - matthewfeickert
+    - ofek