Use Perl for Ruby version script

implementations/json_schemer/version.sh

@@ -4,7 +4,7 @@ set -o errexit
 set -o nounset
 
 # Extract the version of the package (json_schemer) from Gemfile.lock
-json_schemer_version=$(grep -Po '(?<=json_schemer \().*(?=\))' implementations/json_schemer/Gemfile.lock)
+json_schemer_version=$(perl -nle'print $& while m{(?<=json_schemer \().*(?=\))}g' implementations/json_schemer/Gemfile.lock)
 
 # Output the version
 echo "$json_schemer_version"