chore: install google-cloud-testutils (via synth)

noxfile.py

@@ -113,8 +113,7 @@ def system(session):
 
     # Install all test dependencies, then install this package into the
     # virtualenv's dist-packages.
-    session.install("mock", "pytest")
-    session.install("git+https://github.com/googleapis/python-test-utils")
+    session.install("mock", "pytest", "google-cloud-testutils")
     session.install("-e", ".[fastavro,pandas,pyarrow]")
     session.install("-e", ".")
 

synth.metadata

@@ -11,22 +11,22 @@
       "git": {
         "name": ".",
         "remote": "https://github.com/googleapis/python-bigquery-storage.git",
-        "sha": "49b941a207af28a3a30b96cd6eda22b6eda0a0f0"
+        "sha": "9812244202f131142286fc48126ecb633515a6bc"
       }
     },
     {
       "git": {
         "name": "googleapis",
         "remote": "https://github.com/googleapis/googleapis.git",
-        "sha": "bcc476396e799806d3355e87246c6becf6250a70",
-        "internalRef": "306974763"
+        "sha": "28e76243c23cc282efbb288cb558c174e3e5e9ee",
+        "internalRef": "308294748"
       }
     },
     {
       "git": {
         "name": "synthtool",
         "remote": "https://github.com/googleapis/synthtool.git",
-        "sha": "6980131905b652563280e4d2482384d4acc9eafc"
+        "sha": "01b6f23d24b27878b48667ce597876d66b59780e"
       }
     }
   ],