[various] Updates packages to use flutter.compileSdkVersion

[reidbaker]

• Updates compileSdk 34 to flutter.compileSdkVersion.

Related to flutter/flutter/issues/149836
Want to wait a couple of days after
#8700 lands before landing.

Pre-launch Checklist

• I read the [Contributor Guide] and followed the process outlined there for submitting PRs.
• I read the [Tree Hygiene] page, which explains my responsibilities.
• I read and followed the [relevant style guides] and ran the auto-formatter. (Unlike the flutter/flutter repo, the flutter/packages repo does use dart format.)
• I signed the [CLA].
• The title of the PR starts with the name of the package surrounded by square brackets, e.g. [shared_preferences]
• I [linked to at least one issue that this PR fixes] in the description above.
• I updated pubspec.yaml with an appropriate new version according to the [pub versioning philosophy], or this PR is [exempt from version changes].
• I updated CHANGELOG.md to add a description of the change, [following repository CHANGELOG style], or this PR is [exempt from CHANGELOG changes].
• I updated/added relevant documentation (doc comments with ///).
• I added new tests to check the change I am making, or this PR is [test-exempt].
• All existing and new tests are passing.

[reidbaker]

You might wonder why this plugin didnt need to update to 3.27. It is because it was already updated.

[reidbaker]

Ignoring conflicts in changelog and pubspec until after approval since they will keep happening.

[reidbaker]

I think the failure that i am seeing is flutter/flutter#164132

[tarrinneal]

good pigeon test change!

[ryanheise]

Maybe the plugin template should also implement this change too since it currently hardcodes compileSdk to 35 instead of flutter.compileSdkVersion.

Also, just a question about what you've done here. I can see in the example's android/app/build.gradle file that there is this explicit flutter block:

flutter {
source '../..'
}

But in the plugin itself, the android/build.gradle file contains no such explicit flutter block, so I'm curious how the reference to flutter.compileSdkVersion is resolved. Is the idea that it is inherited from whatever app is being built? When I open the plugin in Android Studio, it has a problem resolving the reference to flutter.compileSdkVersion, yet apps will build fine from the command line.

Finally, I question whether this change might be considered as a breaking change, since other plugins or apps that depend on such a plugin that use compileSdk 34 might now stop during the build because the plugin requires compileSdk 35. Do we ignore that sort of thing when considering semantic versioning of plugins?

[reidbaker]

"I question whether this change might be considered as a breaking change, since other plugins or apps that depend on such a plugin that use compileSdk 34 might now stop during the build because the plugin requires compileSdk 35. "

This change also set the minimum flutter verison to 3.27.0 that version of flutter is expecting to compiled with sdk 35. If you were running a version of flutter that expected sdk 34 then you would not get this change. In my mind that is why this is not a breaking change.