fix(ci): green the matrix — importlib.metadata, manylinux_2_28, drop cp38

Three failures on an untouched master (#288), three causes:

1. macos-3.12: `import vpython` itself was broken on fresh 3.12+
   environments — vpython/__init__.py imported pkg_resources, and Python
   3.12 no longer ships setuptools into new environments. Replaced with
   stdlib importlib.metadata (3.8+), and python_requires bumped 3.7→3.8
   to match. This is a real user-facing bug, not just a CI one: anyone on
   a clean 3.12 install hits it.

2. aarch64 cp311/cp312: cbor2 — a hard dependency via autobahn — ships
   only manylinux_2_28 aarch64 wheels for cp311+, so the manylinux2014
   (glibc 2.17) container could not use them and fell back to building
   the C extension from source under QEMU, which fails. Container moved
   to quay.io/pypa/manylinux_2_28_aarch64.

3. aarch64 cp38: Python 3.8 is EOL and the leg fails outright. Dropped.

The windows 3.8/3.9 legs still pass and are left alone — retiring them
is a support-policy decision, not a CI repair.

Closes #288.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01G7y9rTA1r8r8EhEnPSQenR

Author: sspickle

.github/workflows/build.yml

@@ -82,11 +82,16 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        python-version: [cp38-cp38, cp39-cp39, cp310-cp310, cp311-cp311, cp312-cp312]
+        # cp38 dropped: Python 3.8 is EOL and its leg fails outright.
+        python-version: [cp39-cp39, cp310-cp310, cp311-cp311, cp312-cp312]
     runs-on: ubuntu-latest
     env:
       py: /opt/python/${{ matrix.python-version }}/bin/python
-      img: quay.io/pypa/manylinux2014_aarch64
+      # manylinux_2_28, not manylinux2014: cbor2 (a hard dependency via
+      # autobahn) ships only manylinux_2_28 aarch64 wheels for cp311+, so the
+      # 2014 (glibc 2.17) container can't use them and falls back to a
+      # from-source C build that fails under QEMU.
+      img: quay.io/pypa/manylinux_2_28_aarch64
 
     steps:
 

setup.py

@@ -37,7 +37,7 @@
     ],
     ext_modules=extensions,
     install_requires=install_requires,
-    python_requires=">=3.7",
+    python_requires=">=3.8",
     package_data={'vpython': ['vpython_data/*',
                               'vpython_libraries/*',
                               'vpython_libraries/images/*']},

vpython/__init__.py

@@ -1,10 +1,13 @@
-from pkg_resources import get_distribution, DistributionNotFound
+# importlib.metadata, not pkg_resources: fresh Python 3.12+ environments no
+# longer ship setuptools, so `import pkg_resources` raises ModuleNotFoundError
+# the moment `import vpython` runs (caught by CI's macos-3.12 leg).
+from importlib.metadata import version as _dist_version, PackageNotFoundError
 
 from .gs_version import glowscript_version
 
 try:
-    __version__ = get_distribution(__name__).version
-except DistributionNotFound:
+    __version__ = _dist_version(__name__)
+except PackageNotFoundError:
     # package is not installed
     pass
 __gs_version__ = glowscript_version()