chore(deps): update dependency flutter_lints to v6

[renovate]

This PR contains the following updates:

Package	Type	Update	Change
flutter_lints (source)	dev_dependencies	major	^5.0.0 -> ^6.0.0

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Release Notes

flutter/packages (flutter_lints)

v6.0.0

Compare Source

• Updates package:lints dependency to version 6.0.0, with the following changes:
  • adds strict_top_level_inference
  • adds unnecessary_underscores
• Updates minimum supported SDK version to Flutter 3.32/Dart 3.8.

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Configuration

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[github-actions]

LCOV of commit c14a91d during Test Package #122

Summary coverage rate:
  lines......: 7.6% (279 of 3688 lines)
  functions..: no data found
  branches...: no data found

Files changed coverage rate: n/a