feat: Support Alpine

[tienvx]

Thanks @YOU54F for the implementation. Here is the original code master...YOU54F:pact-php:tx-support-alpine

We will need to update the Alpine ci once Github Actions Linux ARM is available.

[coveralls]

Pull Request Test Coverage Report for Build 9136030517

Details

• 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 97.313%

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Totals
Change from base Build 9098735715:	0.0%
Covered Lines:	2282
Relevant Lines:	2345

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💛 - Coveralls

[YOU54F]

🚀 Let there be Alpine!

Nice to be first of the client libraries consuming the FFI to support it properly.

edit: I'll get the plugin index updated shortly (probably in about an hour as have a meeting now) - now done ✅