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

tseaver · web-flow · commit b62b727cc773 · 2021-07-15T12:06:10.000-04:00
diff --git a/testing/constraints-2.7.txt b/testing/constraints-2.7.txt
@@ -0,0 +1,2 @@
+google-cloud-testutils < 1.0dev
+
