Yeah, something like: "version": "v0.1.0",
Note that you should use Semantic Versioning, with a X.Y.Z format, where X is the major version, Y is the minor version, and Z is the patch version. Also, please avoid to use the same version as the software itself. Your version should be independant, because you may release several versions of your language pack which can be compatible with a same Flarum version, that can be confusing.
If you consider your current language pack release as stable, you can tag it as v1.0.0.
