feat: support Elixir 1.14.4+

[paulswartz]

1.14.4 was the first Elixir release to support OTP 26: https://github.com/elixir-lang/elixir/releases/tag/v1.14.4

There doesn't appear to be anything about Oidcc which requires features in 1.15, so Oidcc can express support for slightly earlier versions.

[coveralls]

Pull Request Test Coverage Report for Build 87

• 0 of 0 changed or added relevant lines in 0 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage remained the same at 92.398%

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Totals
Change from base Build 119:	0.0%
Covered Lines:	705
Relevant Lines:	763

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💛 - Coveralls

[maennchen]

Thanks ❤️