chore(deps-dev): Bump gulp-eslint from 3.0.1 to 6.0.0

[dependabot]

Bumps gulp-eslint from 3.0.1 to 6.0.0.

Release notes

Sourced from gulp-eslint's releases.

v6.0.0

• Upgrade to ESLint 6 (#235) a35a203

adametry/gulp-eslint@v5.0.0...v6.0.0

Changelog

Sourced from gulp-eslint's changelog.

6.0.0

• Bump eslint dependency to ^6.0.0 https://eslint.org/blog/2019/06/eslint-v6.0.0-released
• Drop support for Node 6 and 7

5.0.0

• Bump eslint dependency to ^5.0.0 https://eslint.org/blog/2018/06/eslint-v5.0.0-released
• Use destructuring assignment to simplify the code

4.0.2

• Update plugin-error to ^1.0.0

4.0.1

• Make fix option work even if quiet option is also enabled
• Remove deprecated gulp-util dependency and use individual modules instead

4.0.0

• Drop support for linting Stream contents
  • Because almost all, at least widely used tools to handle JavaScript files don't support Streams. They only support either String or Buffer.
• Use Buffer.from(<string>) instead of the deprecated new Buffer(<string>)
  • Note that Buffer.from is only available on Node.js >= 4.5.0.
• Bump eslint dependency to ^4.0.0
• Emit a PluginError when it fails to load an ESLint plugin

Commits

• 5dd78fa 6.0.0
• a35a203 Upgrade to ESLint 6 (#235)
• 40d004f 5.0.0
• 72c3599 use destructuring assignment to simplify the code
• aed571b update dependencies and devDependencies (#224)
• a58a58d 4.0.2
• 0880d1a update plugin-error and mocha
• 1d79ed0 4.0.1
• 8f7e966 replace all HTTP protocols with HTTPS
• b48a04a remove deprecated gulp-util dependency (#213)
• Additional commits viewable in compare view

[phil-davis]

https://github.com/owncloud/contacts/actions/runs/29705455867/job/88241563264?pr=781

46:1  error  Expected indentation of 6 tabs but found make[2]: Leaving directory '/home/runner/work/contacts/contacts'

Lots of these kind of lint errors, and other "real" problems. Work will be needed to do this triple major version bump.

[DeepDiver1975]

Holding: CI is failing (not a rebase conflict). Failing checks: build + Commits semantic + JS Unit. A rebase won't fix this — needs a human/upstream fix.

[phil-davis]

@dependabot rebase