tests: pin 'google-cloud-testutils' to Python 2.7 compatible range (googleapis#506)

tseaver · cojenco · commit 8c1f1b30f6e6 · 2021-10-13T15:02:03.000-07:00
diff --git a/testing/constraints-2.7.txt b/testing/constraints-2.7.txt
@@ -0,0 +1,2 @@
+google-cloud-testutils < 1.0dev
+
