deps: update gax.version to v1.50.1 (#29)

Author: renovate-bot

pom.xml

@@ -68,7 +68,7 @@
     <google.common-protos.version>1.17.0</google.common-protos.version>
     <google.auth.version>0.18.0</google.auth.version>
     <google.http-client.version>1.32.1</google.http-client.version>
-    <gax.version>1.50.0</gax.version>
+    <gax.version>1.50.1</gax.version>
     <grpc.version>1.25.0</grpc.version>
     <protobuf.version>3.10.0</protobuf.version>
     <junit.version>4.12</junit.version>