message: update synapse readme.java.md
diff: @@ -58,8 +58,8 @@ Please also specify `--azure-libraries-for-java=<path to the root directory of y
  ``` yaml $(tag) == 'package-2020-12-01' && $(java) && $(multiapi)
  java:
  - namespace: com.microsoft.azure.management.synapse.v2020-12-01
  - output-folder: $(azure-libraries-for-java-folder)/sdk/synapse/mgmt-v2020-12-01
  + namespace: com.microsoft.azure.management.synapse.v2020_12_01
  + output-folder: $(azure-libraries-for-java-folder)/sdk/synapse/mgmt-v2020_12_01
  regenerate-manager: true
  generate-interface: true
  ```
  \ No newline at end of file
  