Merged PR 67392: 2.7.0 Pre-release

update change logs, composer version bump to 2.7.0

Related work items: #309586

Merged PR 64074: Release 2.6.1

- Merged PR 58609: Allow import summary to be empty
- Merged PR 63551: Replace dummy API creds with functioning creds in shared .env
- Merged PR 63543: PHP 8.4 patch
- Merged PR 64071: Pre-release
- Merge branch 'develop' of ssh.dev.azure.com:v3/dotdigital/ec/dd-php into release/8-4-25

Related work items: #272895, #292232, #292482

Merged PR 58579: Release 2.6.0

### What's new
- Responses with a 429 (Too Many Requests) error code now trigger a specific exception with properties exposing additional information (the call scope, rate limit and time to retry).

### Bug fixes
- `Contact::setDataFields()` no longer breaks if passed an empty array.
- The import summary property is now allowed to be empty.

Related work items: #236362, #270151, #272401

Merge branch 'develop' of ssh.dev.azure.com:v3/dotdigital/ec/dd-php i…

…nto release/2.5.0

Merge branch 'develop' into release/2.4.1

Merge branch 'develop' into release/2.4.0

Merge branch 'develop' into relase/2.3.1

Merged PR 48986: Release 2.3.0

Related work items: #211425, #229536, #229740, #229910, #231234, #231346

Merged PR 48553: Release 2.2.0

Related work items: #227550, #228250

Merge branch 'develop' into release/2.1.0