update gRPC to 1.36.2 (#2096)

@suztomo @ejona changes an INTERNAL error into an UNAVAILABLE error.

Author: elharo

boms/cloud-lts-bom/pom.xml

@@ -58,7 +58,7 @@
     <google.autovalue.version>1.8.1</google.autovalue.version>
     <protobuf.version>3.16.0</protobuf.version>
     <http.version>1.39.2-sp.1</http.version>
-    <io.grpc.version>1.36.1</io.grpc.version>
+    <io.grpc.version>1.36.2</io.grpc.version>
     <!-- We don't use gax-bom because it includes the artifacts with 'testlib' classifier.
         When updating gax.version, update gax.httpjson.version too. -->
     <gax.version>1.64.0-sp.1</gax.version>