[docs] Fix download url in mongodb tutorial (#951)

This closes #951.

docs/content/quickstart/mongodb-tutorial.md

@@ -110,7 +110,7 @@ db.customers.insertMany([
 ```Download links are available only for stable releases.```
 
  - [flink-sql-connector-elasticsearch7_2.11-1.13.2.jar](https://repo.maven.apache.org/maven2/org/apache/flink/flink-sql-connector-elasticsearch7_2.11/1.13.2/flink-sql-connector-elasticsearch7_2.11-1.13.2.jar)
- - [flink-sql-connector-mongodb-cdc-2.2-SNAPSHOT.jar](https://repo1.maven.org/maven2/com/ververica/flink-sql-connector-mongodb-cdc/2.2-SNAPSHOT/flink-sql-connector-postgres-cdc-2.2-SNAPSHOT.jar)
+ - [flink-sql-connector-mongodb-cdc-2.2-SNAPSHOT.jar](https://repo1.maven.org/maven2/com/ververica/flink-sql-connector-mongodb-cdc/2.2-SNAPSHOT/flink-sql-connector-mongodb-cdc-2.2-SNAPSHOT.jar)
 
 4. Launch a Flink cluster, then start a Flink SQL CLI and execute following SQL statements inside: 
 

docs/content/快速上手/mongodb-tutorial-zh.md

@@ -110,7 +110,7 @@ db.customers.insertMany([
 ```下载链接只在已发布的版本上可用```
 
  - [flink-sql-connector-elasticsearch7_2.11-1.13.2.jar](https://repo.maven.apache.org/maven2/org/apache/flink/flink-sql-connector-elasticsearch7_2.11/1.13.2/flink-sql-connector-elasticsearch7_2.11-1.13.2.jar)
- - [flink-sql-connector-mongodb-cdc-2.2-SNAPSHOT.jar](https://repo1.maven.org/maven2/com/ververica/flink-sql-connector-mongodb-cdc/2.2-SNAPSHOT/flink-sql-connector-postgres-cdc-2.2-SNAPSHOT.jar)
+ - [flink-sql-connector-mongodb-cdc-2.2-SNAPSHOT.jar](https://repo1.maven.org/maven2/com/ververica/flink-sql-connector-mongodb-cdc/2.2-SNAPSHOT/flink-sql-connector-mongodb-cdc-2.2-SNAPSHOT.jar)
 
 4. 然后启动 Flink 集群，再启动 SQL CLI.