Add reflection service to grpc server

User can now inspect service definitions (e.g. with grpcurl).

spring-cloud-function-grpc/pom.xml

@@ -31,6 +31,11 @@
 		    <artifactId>grpc-protobuf</artifactId>
 		    <version>${grpc.version}</version>
 		</dependency>
+		<dependency>
+		    <groupId>io.grpc</groupId>
+		    <artifactId>grpc-services</artifactId>
+		    <version>${grpc.version}</version>
+		</dependency>
 		<dependency>
 		    <groupId>io.grpc</groupId>
 		    <artifactId>grpc-stub</artifactId>