Document support for Python versions in pyproject.toml

Author: jdufresne

pyproject.toml

@@ -21,6 +21,11 @@ classifiers = [
     "Programming Language :: Python",
     "Programming Language :: Python :: 3",
     "Programming Language :: Python :: 3 :: Only",
+    "Programming Language :: Python :: 3.7",
+    "Programming Language :: Python :: 3.8",
+    "Programming Language :: Python :: 3.9",
+    "Programming Language :: Python :: 3.10",
+    "Programming Language :: Python :: 3.11",
 ]
 dependencies = []
 dynamic = ["version"]