fix: clean up nox sessions to uniformly displays package versions for debug purposes (#777)

* specify a particular version of bigquery to debug

* fix: updates noxfile to cleanup debugging code

* Update noxfile.py

Author: chalmerlowe

noxfile.py

@@ -527,16 +527,10 @@ def prerelease_deps(session):
         "requests",
     ]
     session.install(*other_deps)
-    session.run("python", "-m", "pip", "freeze")
 
     # Print out package versions.
     session.run("python", "-m", "pip", "freeze")
 
-    session.run(
-        "python", "-c", "import google.protobuf; print(google.protobuf.__version__)"
-    )
-    session.run("python", "-c", "import grpc; print(grpc.__version__)")
-
     session.run("py.test", "tests/unit")
 
     system_test_path = os.path.join("tests", "system.py")