Livecheck regex with version in url path

[Steven Smith]

How does one write a live check for ghc, whose version lives in the url path?

https://downloads.haskell.org/ghc/8.8.1/ghc-8.8.1-src.tar.xz <https://downloads.haskell.org/ghc/8.8.1/ghc-8.8.1-src.tar.xz>

I’ve tried stuff like the following, without success:

livecheck.type      regex                                                       
livecheck.url       https://downloads.haskell.org/~${name}/${version}           
livecheck.regex     (\\d+(?:\\.\\d+){1,4})/${name}-\\1-src${extract.suffix} 
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