Bump up to v4.0

Author: headius

src/main/java/org/jruby/prism/parser/ParserPrismBase.java

@@ -212,7 +212,7 @@ private byte[] generateMetadata(String fileName, int lineNumber, Encoding encodi
         metadata.append(flags);
 
         // version
-        metadata.append(ParsingOptions.SyntaxVersion.V3_4.getValue());
+        metadata.append(ParsingOptions.SyntaxVersion.V4_0.getValue());
 
         // Do not lock encoding
         metadata.append(0);