Add trove classifiers for platform support

Author: jeromekelleher

pyproject.toml

@@ -26,7 +26,10 @@ requires-python = ">=3.9"
 classifiers = [
   "Development Status :: 3 - Alpha",
   "License :: OSI Approved :: Apache Software License",
-  "Operating System :: OS Independent",
+  "Operating System :: POSIX",
+  "Operating System :: POSIX :: Linux",
+  "Operating System :: MacOS",
+  "Operating System :: MacOS :: MacOS X",
   "Intended Audience :: Science/Research",
   "Programming Language :: Python",
   "Programming Language :: Python :: 3",