fix(ruby): fix versioning increment (#4144)

lib/versioning/ruby/version.js

@@ -47,7 +47,7 @@ const incrementPatch = (ptch, pre) => (pre.length === 0 ? ptch + 1 : ptch);
 
 // istanbul ignore next
 const increment = (from, to) => {
-  const { major: maj, minor: min, patch: ptch, pre } = parse(from);
+  const { major: maj, minor: min, patch: ptch, prerelease: pre } = parse(from);
 
   let nextVersion;
   switch (diff(from, adapt(to, from))) {