do not treat all mentions of $Package::Name::VERSION as an assignment
Test pruning multiple files

PruneCruft and PruneFiles currently failing
Copy files list to break reference when Pruning

fixes previous "remove multiple" tests.
switch all uses of JSON.pm to JSON::MaybeXS
changelog
v5.028

        - fix regression in [PkgVersion] that made false-positive
          identifications for pre-existing assignments to $VERSION
        - try avoid cases in which plugin code directly modifies file list
        - switch, tentatively, to JSON::MaybeXS
find() returns an arrayref on success or false-but-defined on failure
test metadata and prerequisites directly
don't load JSON when we don't use it
v5.029

        - fix new error in [PkgVersion] when a module had no package
          statements
        - further rip out use of JSON.pm
additional tests for [NextRelease] Changes munging
use the original Changes content as a base for munging, rather than whatever is in the repo after release

This allows other AfterRelease plugins to copy the Changes file from the built
distribution back to the repo and commit it, before we add in the {{$NEXT}}
line here.