remove --pre flag

Author: ohmayr

packages/gapic-generator/noxfile.py

@@ -498,7 +498,7 @@ def showcase_pqc(
     """Run the Showcase PQC verification test suite against grpcio 1.83+ over standard TLS."""
     with showcase_library(session, templates=templates, other_opts=other_opts):
         session.install("pytest", "pytest-asyncio")
-        session.install("--pre", "--upgrade", "grpcio>=1.83.0", "grpcio-status>=1.83.0")
+        session.install("--upgrade", "grpcio>=1.83.0", "grpcio-status>=1.83.0")
         session.run("py.test", "--quiet", "--tls", *(session.posargs or ["tests/system/test_pqc.py"]), env=env)