chore: fix build of cli package on OSX machines

[svenjacobs]

Trying to build this project on my computer (macOS 12.2.1, Node 16.14, pnpm 6.31.0) I get the following error for packages/cli:

> @typesafe-i18n/cli@ build /Users/sven/Dev/Projects/Personal/typesafe-i18n/packages/cli
> tsm esbuild.ts

(node:50854) ExperimentalWarning: --experimental-loader is an experimental feature. This feature could change at any time
(Use `node --trace-warnings ...` to show where the warning was created)
(node:50854) DeprecationWarning: Obsolete loader hook(s) supplied and will be ignored: getFormat, transformSource
✘ [ERROR] No loader is configured for ".node" files: ../../node_modules/.pnpm/fsevents@2.3.2/node_modules/fsevents/fsevents.node

    ../../node_modules/.pnpm/fsevents@2.3.2/node_modules/fsevents/fsevents.js:13:23:
      13 │ const Native = require("./fsevents.node");
         ╵                        ~~~~~~~~~~~~~~~~~

 ELIFECYCLE  Command failed with exit code 1.

According to this comment of the esbuild project, a custom plugin needs to be added.

In this PR, I added the missing plugin. I also added a .nvmrc so that maintainers (that hopefully use nvm) are using the correct Node version.

[ivanhofer]

@svenjacobs thanks for investigating and creating this PR.
I'm using volta in favour over nvm so I added a commit that locks the version down also for volta users.