jar extensions should be mapped to java in languages.ts

[jordancontrast]

The artifacts output generated will contain "sourceLanguage": "unknown" if the artifact uri has a jar extension.
Currently, languages.ts only returns "sourceLanguage": "Java" is the extension is java.
I propose that languages.ts should contain jar: 'Java',

[nvuillam]

I'm trying to remember where I found language.ts (I obviously not written it ^^ )

@jordancontrast as SARIF does not enforces a specific list (the property type is string), i'll validate your Pull Request if you add the update you are suggesting :)