Added PR links to changelog for spark configuration renames. (Azure#21175)

Added PR links to changelog for spark configuration renames.

Author: moderakh

sdk/cosmos/azure-cosmos-spark_3-1_2-12/CHANGELOG.md

@@ -5,9 +5,9 @@
 ### 4.0.0-beta.3 (2021-05-05)
 * Cosmos DB Spark 3.1.1 Connector Preview `4.0.0-beta.3` Release.
 #### Configuration Renames
-* Renamed data source name "cosmos.items" to "cosmos.oltp".
-* Renamed data source name "cosmos.changeFeed" to "cosmos.oltp.changeFeed".
-* Configuration renamed. See [Configuration-Reference](https://github.com/Azure/azure-sdk-for-java/blob/master/sdk/cosmos/azure-cosmos-spark_3-1_2-12/docs/configuration-reference.md) for more details.
+* Renamed data source name `cosmos.items` to `cosmos.oltp`, See [PR](https://github.com/Azure/azure-sdk-for-java/pull/21121). 
+* Renamed data source name `cosmos.changeFeed` to `cosmos.oltp.changeFeed`, see [PR](https://github.com/Azure/azure-sdk-for-java/pull/21121).
+* Configuration renamed. See [PR](https://github.com/Azure/azure-sdk-for-java/pull/21004) for list of changes. See [Configuration-Reference](https://github.com/Azure/azure-sdk-for-java/blob/master/sdk/cosmos/azure-cosmos-spark_3-1_2-12/docs/configuration-reference.md) for more details.
 
 #### Key Bug Fixes
 * Added validation for all config-settings with a name starting with "spark.cosmos."