Default version command does not work for esmodule packages

[JakeStanger]

If you use the now stable esmodule resolution (by including "type": "module" in your package.json), the default version command throws an error trying to get the main module.

λ fe version
/home/jake/Programming/filebrowser2/node_modules/args/lib/version.js:26
  const pkg = findPackage(path.dirname(process.mainModule.filename))
                                                          ^

TypeError: Cannot read properties of undefined (reading 'filename')
    at module.exports [as showVersion] (/home/jake/Programming/filebrowser2/node_modules/args/lib/version.js:26:59)
    at Args.runCommand (/home/jake/Programming/filebrowser2/node_modules/args/lib/utils.js:306:37)
    at module.exports [as parse] (/home/jake/Programming/filebrowser2/node_modules/args/lib/parse.js:63:10)
    at file:///home/jake/Programming/filebrowser2/lib/cli.js:9:20
    at ModuleJob.run (node:internal/modules/esm/module_job:198:25)
    at async Promise.all (index 0)
    at async ESMLoader.import (node:internal/modules/esm/loader:409:24)
    at async loadESM (node:internal/process/esm_loader:85:5)
    at async handleMainPromise (node:internal/modules/run_main:61:12)

Node.js v18.3.0

I don't think there's going to be a very nice way around this unfortunately, as the concept of a "main" module is kinda thrown out the window. You can use meta.import.url to get the current module's URL, and could possibly do a walk up the filetree, but I'm not sure how reliable that'll be.

If the command can't be easily fixed, I propose args does a check to see if process.mainModule is defined, and if not just disables the version command.