Update InterceptPoint.java (#1776)

Using Mongo 2.14.3, we found that :" java. lang. ClassNotFoundException: Can't find MongoDBCollection Method Interceptor",  must use "org.apache.skywalking.apm.plugin.mongodb.v2.MongoDBCollectionMethodInterceptor" to solve this problem.

apm-sniffer/apm-sdk-plugin/mongodb-2.x-plugin/src/main/java/org/apache/skywalking/apm/plugin/mongodb/v2/define/InterceptPoint.java

@@ -25,7 +25,7 @@ import org.apache.skywalking.apm.agent.core.plugin.interceptor.InstanceMethodsIn
  * @author liyuntao
  */
 public abstract class InterceptPoint implements InstanceMethodsInterceptPoint {
-    private static final String MONGDB_METHOD_INTERCET_CLASS = "MongoDBCollectionMethodInterceptor";
+    private static final String MONGDB_METHOD_INTERCET_CLASS = "org.apache.skywalking.apm.plugin.mongodb.v2.MongoDBCollectionMethodInterceptor";
 
     @Override
     public String getMethodsInterceptor() {