Messaging API Update - November 2021 - Support text enter sticker msg.

[kkdai]

Fix #295

• You can now retrieve the text entered by the user in a message sticker
• You can now retrieve up to 1000 user IDs of friends

Reference: https://developers.line.biz/en/news/2021/11/09/messaging-api-update/

[codecov-commenter]

Codecov Report

Merging #298 (97bf5a0) into master (a1681df) will not change coverage.
The diff coverage is n/a.

❗ Current head 97bf5a0 differs from pull request most recent head b74da79. Consider uploading reports for the commit b74da79 to get more accurate results

@@           Coverage Diff           @@
##           master     #298   +/-   ##
=======================================
  Coverage   78.50%   78.50%           
=======================================
  Files          37       37           
  Lines        2870     2870           
=======================================
  Hits         2253     2253           
  Misses        486      486           
  Partials      131      131           

Impacted Files	Coverage Δ
linebot/event.go	97.88% <ø> (ø)

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[kkdai]

@clsung Thank you, would you please check it again?

[clsung]

My bad in previous review, it should be StickerResourceTypeMessage , and please remove StickerResourceTypePerStickerText and StickerResourceTypeNameText.

[kkdai]

@clsung I update to previous version, please let me know if you still have any question.