Upgrade cargo-generate-rpm to support %posttrans

[ximon18]

As per https://docs.pagure.org/packaging-guidelines/Packaging%3AScriptlets.html %posttrans is the only way to change/remove content installed by a previous package (either an earlier version of the package being installed or a package that is obsoleted by the package being installed) because RPM installs the new package first and only then uninstalls the old package, but the new package gets a final chance to act in the %posttrans phase.

https://github.com/cat-in-136/cargo-generate-rpm/releases/tag/v0.14.0 added support for %posttrans but all later releases (0.14.1, 0.15.0, 0.15.1, 0.15.2) include fixes for regressions in earlier releases so we may want an even higher version - except that 0.15.0 removes support for older O/S's which might break us, need to check.