📦 Release web-features@2.6.1

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This is a generated release pull request. Don't merge if you're not ready to carry out the release.

## What's New

- 71% coverage of BCD

## What's Changed
* Add missing flexbox, font-face and text-emphasis keys by @jamesnw in https://github.com/web-platform-dx/web-features/pull/2215
* Advance review date on the Baseline definition by @ddbeck in https://github.com/web-platform-dx/web-features/pull/2213
* Add missing masks keys by @jamesnw in https://github.com/web-platform-dx/web-features/pull/2214
* Bump @mdn/browser-compat-data from 5.6.14 to 5.6.15 by @dependabot in https://github.com/web-platform-dx/web-features/pull/2219

**Full Changelog**: https://github.com/web-platform-dx/web-features/compare/v2.6.0...v2.6.1