Plugin release 4.0.0

[LTPhantom]

Description

Replace this paragraph with a description of what this PR is doing. If you're modifying existing behavior, describe the existing behavior, how this PR is changing it, and what motivated the change.

Related Issues

*Replace this paragraph with a list of issues related to this PR from the issue database. Indicate, which of these issues are resolved or fixed by this PR.

Checklist

Before you create this PR confirm that it meets all requirements listed below by checking the relevant checkboxes ([x]).
This will ensure a smooth and quick review process. Updating the pubspec.yaml and changelogs is not required.

• I read the Contributor Guide and followed the process outlined there for submitting PRs.
• My PR includes unit or integration tests for all changed/updated/fixed behaviors (See Contributor Guide).
• All existing and new tests are passing.
• I updated/added relevant documentation (doc comments with ///).
• The analyzer (flutter analyze) does not report any problems on my PR.
• I read and followed the Flutter Style Guide.
• I signed the CLA.
• I am willing to follow-up on review comments in a timely manner.

Breaking Change

Does your PR require plugin users to manually update their apps to accommodate your change?

• Yes, this is a breaking change (please indicate a breaking change in CHANGELOG.md and increment major revision).
• No, this is not a breaking change.

[jjliu15]

It looks like the iOS unit test testEncodeDecodeRequestConfiguration failed: https://github.com/googleads/googleads-mobile-flutter/actions/runs/7093442769/job/19306819114?pr=972. From the release notes it looks like there have been some changes to GADRequestConfiguration in some recent releases: https://developers.google.com/admob/ios/rel-notes

[LTPhantom]

It looks like the iOS unit test testEncodeDecodeRequestConfiguration failed: https://github.com/googleads/googleads-mobile-flutter/actions/runs/7093442769/job/19306819114?pr=972. From the release notes it looks like there have been some changes to GADRequestConfiguration in some recent releases: https://developers.google.com/admob/ios/rel-notes

Yeah, it seems that new changes will be needed to be able to update to SDK version 10.14.0. For this release, I changed it from 10.9.0 to 10.11.0 as expected here. I created a backlog task to work on updating the deprecated methods for iOS.