chore(v4.2.x): release 4.2.7

[github-actions]

🤖 I have created a release beep boop

4.2.7 (2023-01-13)

Bug Fixes

• Fix exception enabling captions on HLS (#4894) (45b3705), closes #4889
• Fix flattenedCues in WebVttGenerator (#4867) (2b37820)
• Fix legacy codec support by rewriting codec metadata (#4858) (102c3d9)
• Fix media source duration when using sequence mode (#4848) (177638c)
• Fix parsing error on Chromecast when resyncing HLS (#4869) (13e7481), closes #4589
• Fix potential AV sync issues after seek or adaptation (#4886) (ac3afb4), closes #4589
• Fix potential duplicate segments, AV sync issues (#4884) (45b6ccb), closes #4589
• HLS: Fix discontinuity tracking (#4881) (13d29fd), closes #4589
• HLS: Fix support for mixed AES-128/NONE decryption (#4847) (e866903)
• Make encoding problem detection more robust (#4885) (208c2e2), closes #4589
• Release region timeline when unloading (#4871) (af1ee47), closes #4850
• Sync each segment against EXT-X-PROGRAM-DATE-TIME (#4870) (fadbeb6)
• Treat regions uniquely (#4841) (7952af9), closes #4839
• ui: Avoid submitting form if player is inside form (#4866) (c7db48a), closes #4861

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[github-actions]

🤖 Release is at https://github.com/shaka-project/shaka-player/releases/tag/v4.2.7 🌻