New package: guile-json-4.7.3

[zipcode]

Testing the changes

• I tested the changes in this PR: YES

New package

• This new package conforms to the package requirements: YES

Local build testing

• I built this PR locally for my native architecture, (x86_64)
• I built this PR locally for these architectures (if supported. mark crossbuilds):
  • aarch64-musl (crossbuild)
  • armv7l (crossbuild)
  • armv6l-musl (crossbuild)
  • armv6l (crossbuild) (because CONTRIBUTING.md said to)