Bug(language code): lowercase dashed language codes fail to present

[AmitMY]

Is there an existing issue for this?

• [X] I have searched the existing issues

Which Transloco package(s) are the source of the bug?

Transloco

Is this a regression?

No

Current behavior

if trying to load language code zh-cn for example, the files indeed load correctly, but transloco throws warnings in the console:

Missing translation for 'zhCn.title'

and does not display the text correctly.

Expected behavior

lowercase zh-cn should work, same as zh-CN uppercase.

Please provide the environment you discovered this bug in

Transloco: 4.1.0
Angular: 14.0.1
Package Manager: npm
OS: macOS