Update dependency lints to v6

[renovate]

This PR contains the following updates:

Package	Type	Update	Change
lints (source)	dev_dependencies	major	^4.0.0 → 6.1.0

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Release Notes

dart-lang/core (lints)

v6.1.0

Compare Source

• recommended:
  • added use_null_aware_elements (#​899)
  • added no_wildcard_variable_uses (#​832)
• Run dart format with the new style.

v6.0.0

Compare Source

• core:
  • added strict_top_level_inference (#​836)
• recommended:
  • added unnecessary_underscores (#​856)
• Require Dart 3.8.

v5.1.1

Compare Source

• Updated the SDK lower bound to 3.6.
• Move to dart-lang/core monorepo.

v5.1.0

Compare Source

• core:
  • added unintended_html_in_doc_comment (dart-lang/lints#192)
• Updated the SDK lower bound to 3.6 (dev).

v5.0.0

Compare Source

• recommended:
  • added invalid_runtime_check_with_js_interop_types (dart-lang/lints#188)
  • added unnecessary_library_name (dart-lang/lints#181)
  • removed avoid_null_checks_in_equality_operators (dart-lang/lints#200)
• Updated the SDK lower-bound to 3.5.

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