gRPC Server: Fix java.lang.NoClassDefFoundError for Log4j Logger

Explicitly add log4j-api and log4j-core modules as runtime dependencies when running via the main method of the OpenNLPGrpcServer class to resolve missing class error.

Author: rzo1

opennlp-grpc/opennlp-grpc-service/pom.xml

@@ -65,6 +65,20 @@
             <scope>runtime</scope>
         </dependency>
 
+        <dependency>
+            <groupId>org.apache.logging.log4j</groupId>
+            <artifactId>log4j-core</artifactId>
+            <version>${log4j2.version}</version>
+            <scope>runtime</scope>
+        </dependency>
+
+        <dependency>
+            <groupId>org.apache.logging.log4j</groupId>
+            <artifactId>log4j-api</artifactId>
+            <version>${log4j2.version}</version>
+            <scope>runtime</scope>
+        </dependency>
+
         <dependency>
             <groupId>org.junit.jupiter</groupId>
             <artifactId>junit-jupiter-api</artifactId>