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

Author: ruanhang1993

docs/data/jdbc.yml

@@ -17,7 +17,7 @@
 ################################################################################
 
 version: 3.3.0
-flink_compatibility: [1.19, 1.20]
+flink_compatibility: ['1.19', '1.20']
 variants:
   - maven: flink-connector-jdbc
     sql_url: https://repo.maven.apache.org/maven2/org/apache/flink/flink-connector-jdbc/$full_version/flink-connector-jdbc-$full_version.jar