enable but skip unit-3.7 and unit-3.8 presubmits

Author: ohmayr

packages/google-cloud-pubsub/noxfile.py

@@ -41,6 +41,8 @@
 DEFAULT_PYTHON_VERSION = "3.14"
 
 UNIT_TEST_PYTHON_VERSIONS: List[str] = [
+    "3.7",
+    "3.8",
     "3.9",
     "3.10",
     "3.11",
@@ -237,6 +239,9 @@ def install_unittest_dependencies(session, *constraints):
 def unit(session, protobuf_implementation):
     # Install all test dependencies, then install this package in-place.
 
+    if session.python in ["3.7", "3.8"]:
+        session.skip(f"Python {session.python} is no longer supported.")
+
     if protobuf_implementation == "cpp" and session.python in (
         "3.11",
         "3.12",