Bumped tool versions.

VOL-2647

Change-Id: I048103aa4fd54bae5682aa67c2c238c7001da458
diff --git a/docker/protoc.Dockerfile b/docker/protoc.Dockerfile
index 3fa0829..bce36c1 100644
--- a/docker/protoc.Dockerfile
+++ b/docker/protoc.Dockerfile
@@ -12,7 +12,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-FROM golang:1.13.5-alpine as build
+FROM golang:1.13.8-alpine as build
 
 ARG PROTOC_VERSION
 ARG PROTOC_GEN_GO_VERSION