Fixup CHANGELOG.md to have correct changenotes for v1.44.75 and 74.
Fixes the SDK's changelog to have correct changenotes for v1.44.75 and v1.44.74.
Release v1.44.75 (2022-08-11)
===
-Release v1.44.74 (2022-08-11)
-===
-
### Service Client Updates
* `service/backupstorage`: Adds new service
* `service/glue`: Updates service API
* Add support for Python 3.9 AWS Glue Python Shell jobs
* `service/privatenetworks`: Adds new service
+Release v1.44.74 (2022-08-11)
+===
+
### SDK Enhancements
* `service/dynamodb/dynamodbattribute`: Add String method to UnixTime
* Adds a `String` method to `UnixTime`, so that when structs with this field get logged it prints a human readable time.
