Update kotlin & gradle versions to fix build errors with Flutter 2.10.3

[abhlabs]

These updates correct a build error I encountered after upgrading Flutter to 2.10.3:

e: c:\FlutterDev\flutter\.pub-cache\hosted\pub.dartlang.org\disk_space-0.2.1\android\src\main\kotlin\de\appgewaltig\disk_space\DiskSpacePlugin.kt: (14, 6): Class 'kotlin.jvm.JvmStatic' was compiled with an incompatible version of Kotlin. The binary version of its metadata is 1.5.1, expected version is 1.1.16.
The class is loaded from C:/Users/ahart/.gradle/caches/transforms-3/386454215e6950cb1162d1da9ff12466/transformed/jetified-kotlin-stdlib-1.5.31.jar!/kotlin/jvm/JvmStatic.class

I did not update the changelog or the readme.

First PR, so apologies if I've done anything wrong, please let me know.

[ekuleshov-idexx]

@mboeddeker any chance this PR could be integrated and a new disk_space plugin update released?

[harrowmykel]

@ekuleshov-idexx @abhlabs Hey, ich habe taken over the maintenance of this plugin

check it out here

https://pub.dev/packages/disk_space_plus