Bump grpc-protobuf from 1.32.2 to 1.53.0 in /examples

Bumps [grpc-protobuf](https://github.com/grpc/grpc-java) from 1.32.2 to 1.53.0.
- [Release notes](https://github.com/grpc/grpc-java/releases)
- [Commits](grpc/grpc-java@v1.32.2...v1.53.0)

---
updated-dependencies:
- dependency-name: io.grpc:grpc-protobuf
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <support@github.com>

examples/pom.xml

@@ -13,7 +13,7 @@
     <!-- change to the version you want to use. -->
     <jetty.version>9.4.41.v20210516</jetty.version>
     <opencensus.version>0.28.3</opencensus.version> <!-- LATEST_OPENCENSUS_RELEASE_VERSION -->
-    <grpc.version>1.32.2</grpc.version> <!-- CURRENT_GRPC_VERSION -->
+    <grpc.version>1.53.0</grpc.version> <!-- CURRENT_GRPC_VERSION -->
   </properties>
   <dependencies>
     <dependency>