chore: add breaking changes entry to 1.122.0 release

This was missed by the auto bump script since the pull request -
#16329 - was merged without squash.

CHANGELOG.md

@@ -4,6 +4,12 @@ All notable changes to this project will be documented in this file. See [standa
 
 ## [1.122.0](https://github.com/aws/aws-cdk/compare/v1.121.0...v1.122.0) (2021-09-08)
 
+### ⚠ BREAKING CHANGES TO EXPERIMENTAL FEATURES
+
+* **assertions:** `hasOutput(props: any)` becomes `hasOutput(logicalId: string, props: any)`
+* **assertions:** `findOutputs(props: any = {})` becomes `findOutputs(logicalId: string, props: any = {})`
+* **assertions:** `hasMapping(props: any)` becomes `hasMapping(logicalId: string, props: any)`
+* **assertions:** `findMappings(props: any = {})` becomes `findMappings(logicalId: string, props: any = {})`
 
 ### Features
 
@@ -24,6 +30,7 @@ All notable changes to this project will be documented in this file. See [standa
 ### Bug Fixes
 
 * **apigatewayv2:** some methods of the `defaultStage` are not available without casting it to `IHttpStage` ([#15607](https://github.com/aws/aws-cdk/issues/15607)) ([27a0113](https://github.com/aws/aws-cdk/commit/27a0113ac68a05360faa22fa8897609f2f90b764))
+* **assertions:** output and mapping assertions do not accept logical id ([#16329](https://github.com/aws/aws-cdk/issues/16329)), closes [#16242](https://github.com/aws/aws-cdk/issues/16242)
 * **assets:** run executable command of container assets in cloud assembly root directory ([#16094](https://github.com/aws/aws-cdk/issues/16094)) ([c2852c9](https://github.com/aws/aws-cdk/commit/c2852c9c524a639a312bf296f7f23b0e3b112f6b)), closes [#15721](https://github.com/aws/aws-cdk/issues/15721)
 * **autoscaling:** EbsDeviceVolumeType.IO2 is not a valid CloudFormation value ([#16028](https://github.com/aws/aws-cdk/issues/16028)) ([492d33b](https://github.com/aws/aws-cdk/commit/492d33b27bc5b935e3da75f0bddd875bb6f9c15d)), closes [#16027](https://github.com/aws/aws-cdk/issues/16027)
 * **cli:** 'deploy' and 'diff' silently does nothing when given unknown stack name ([#16150](https://github.com/aws/aws-cdk/issues/16150)) ([74776f3](https://github.com/aws/aws-cdk/commit/74776f393462f7e7d23cb1953ef786a823adc896)), closes [#15866](https://github.com/aws/aws-cdk/issues/15866)