[VOL-4289]  Proto changes for gRPC migration

Change-Id: I317a0a865ccf78d0c37aa229c50d293a3f66c8bb
diff --git a/tox.ini b/tox.ini
old mode 100644
new mode 100755
index 0f32f70..8d89806
--- a/tox.ini
+++ b/tox.ini
@@ -13,7 +13,7 @@
 ; limitations under the License.
 
 [tox]
-envlist = py27,py35,py36,py37
+envlist = py27,py35,py36,py37,py38
 skip_missing_interpreters = true
 
 [testenv]