chore(deps): add grpc-google-common-protos to the bom (#144)

It's not used by this client, but this client uses proto-google-common-protos,
and the hbase adapter uses grpc-google-common-protos. So we will use the deps
bom to align the 2. Ideally we would use google-common-protos-bom, but that doesn't
exists

Author: igorbernstein2

google-cloud-bigtable-deps-bom/pom.xml

@@ -144,6 +144,11 @@
         <artifactId>proto-google-common-protos</artifactId>
         <version>${google.common-protos.version}</version>
       </dependency>
+      <dependency>
+        <groupId>com.google.api.grpc</groupId>
+        <artifactId>grpc-google-common-protos</artifactId>
+        <version>${google.common-protos.version}</version>
+      </dependency>
       <dependency>
         <groupId>com.google.api.grpc</groupId>
         <artifactId>proto-google-iam-v1</artifactId>