Bug#964320: ruby-http-parser: hard codes ruby path in debian/rules which breaks backports build and future ruby transitions

[Pirate Praveen]

Package: ruby-http-parser
Version: 1.2.1-3
Severity: important
In debian/rules ruby version 2.7.0 is hard coded which breaks backports 
and future ruby transitions. Supported ruby version should be 
dynamically detected.