Could not find jruby in C:\logstash-7.5.1\vendor\jruby

logstash-7.5.1
Win10/64
jdk1.8.0_241

I'm following the windows installation instructions and have setup the Java paths. I also installed JRuby in case it was needed but when I still get

PS C:\logstash-7.5.1> ./bin/logstash.bat
"could not find jruby in C:\logstash-7.5.1\vendor\jruby"

I didn't have a vendor directory so created one with no change to the error.

How do I resolve this?

Thanks.