rngconverter README.md contains invalid sample commands

[frogcoder]

The sample commands in the rngconverter README.md no longer works. The command now takes two mandatory arguments, first one being the input path, the second is the output path.

Also, the compiles outputs in the target subdirectory does not include a rngconvert.jar. It is now msv-rngconverter-2022.8-SNAPSHOT-jar-with-dependencies.jar. A sample command might look like this.

java -jar .\msv-rngconverter-2022.8-SNAPSHOT-jar-with-dependencies.jar myschema.xsd result.rng

The original sample command is

java -jar rngconv.jar myschema.xsd > result.rng

Not sure about the DTD one though

java -jar rngconv.jar -dtd myschema.dtd > result.rng