chore(deps-dev): Update sass requirement from ^1.76.0 to ^1.77.4 in /example

[dependabot]

Updates the requirements on sass to permit the latest version.

Release notes

Sourced from sass's releases.

Dart Sass 1.77.4

To install Sass 1.77.4, download one of the packages below and add it to your PATH, or see the Sass website for full installation instructions.

Changes

Embedded Sass

• Support passing Version input for fatalDeprecations as string over embedded protocol.

• Fix a bug in the JS Embedded Host where Version could be incorrectly accepted as input for silenceDeprecations and futureDeprecations in pure JS.

See the full changelog for changes in earlier releases.

Changelog

Sourced from sass's changelog.

1.77.4

Embedded Sass

• Support passing Version input for fatalDeprecations as string over embedded protocol.

• Fix a bug in the JS Embedded Host where Version could be incorrectly accepted as input for silenceDeprecations and futureDeprecations in pure JS.

1.77.3

Dart API

• Deprecation.duplicateVariableFlags has been deprecated and replaced with Deprecation.duplicateVarFlags to make it consistent with the duplicate-var-flags name used on the command line and in the JS API.

1.77.2

• Don't emit deprecation warnings for functions and mixins beginning with __.

• Allow user-defined functions whose names begin with _ and otherwise look like vendor-prefixed functions with special CSS syntax.

Command-Line Interface

• Properly handle the --silence-deprecation flag.

• Handle the --fatal-deprecation and --future-deprecation flags for --interactive mode.

1.77.1

• Fix a crash that could come up with importers in certain contexts.

1.77.0

• Don't throw errors for at-rules in keyframe blocks.

1.76.0

• Throw errors for misplaced statements in keyframe blocks.

• Mixins and functions whose names begin with -- are now deprecated for forwards-compatibility with the in-progress CSS functions and mixins spec. This deprecation is named css-function-mixin.

1.75.0

... (truncated)

Commits

• 21eeb4d Parse Deprecation.forVersion on compiler side (#2248)
• 1073c7b Generate deprecations list from the language repo (#2253)
• fc24fec Use pubspec_parse dependency equality (#2254)
• 5121eb1 Don't treat underscores as hyphens for the purpose of error checking (#2247)
• bdc08fd Merge pull request #2246 from sass/deprecation-cli
• 9a9e483 Add a test to ensure the sass_api dartdoc version matches sass
• 8c48a01 Expand dartdoc range for sass_api to match sass
• c9f0d3f Fix deprecation flags in the CLI and add tests
• 54a6dec Bump lints from 3.0.0 to 4.0.0 (#2242)
• 372f15c Fix MapExtensions.getOption() for nullable types (#2241)
• Additional commits viewable in compare view

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[dependabot]

Superseded by #2121.