Redirect url to search page and replace hyphens with space

Say for instance I have a url /support/plugin/redirection-plugin/ that resolved to a 404 code but I want to redirect it to the search page like so

?search=redirection%20plugin

what would I add there to to replace the hyphen with %20?

Thus far I have
Source URL: ^/(.*)\/(.*)\/(.*)/
Target URL: ?search=$3
Just that I get
?search=redirection-plugin
but I want
?search=redirection%20plugin