Drop Python 3.8 from PYTHON_VERSIONS, as not supported by protobuf 6.30

Closes #422

Author: aaliddell

modules/python/MODULE.bazel

@@ -10,7 +10,6 @@ bazel_dep(name = "rules_proto_grpc", version = "0.0.0.rpg.version.placeholder")
 bazel_dep(name = "rules_python", version = "1.4.1")
 
 PYTHON_VERSIONS = [
-    "3.8",
     "3.9",
     "3.10",
     "3.11",