Added CHANGELOG to Azure Batch SDK data plane directory (Azure#20293)

* Added CHANGELOG to Azure Batch SDK data plane directory

* Removed comment change documentation and fixed property spelling

Author: NickKouds

sdk/batch/batch/CHANGELOG.md

@@ -0,0 +1,15 @@
+# Release History
+
+## 10.1.0 (2022-02-09)
+
+### Features
+
+- Added property `uploadHeaders` to `OutputFileBlobContainerDestination`.
+  - Allows users to set custom HTTP headers on resource file uploads.
+  - Array of type HttpHeader (also being added).
+- Added boolean property `allowTaskPreemption` to `JobSpecification`, `CloudJob`, `JobAddParameter`, `JobPatchParameter`, `JobUpdateParameter`
+  - Mark Tasks as preemptible for higher priority Tasks (requires Comms-Enabled or Single Tenant Pool).
+
+
+### Bugs Fixed
+- Fixed missing SharedKeyCredentials class export.