[hotfix][docs] Use string in flink_compatibility for jdbc connector

Author: ruanhang1993

docs/data/jdbc.yml

@@ -17,7 +17,7 @@
 ################################################################################
 
 version: 4.0.0
-flink_compatibility: [2.0]
+flink_compatibility: ['2.0']
 variants:
   - maven: flink-connector-jdbc
     sql_url: https://repo.maven.apache.org/maven2/org/apache/flink/flink-connector-jdbc-core/$full_version/flink-connector-jdbc-core-$full_version.jar