Fix tests on macOS and execute during CI

[lucas-koehler]

Is your feature request related to a problem? Please describe.

Tests currently don't work on MacOS and, thus, are not executed during CI.

Describe the solution you'd like

The tests should be fixed and run during CI.

[DrewHoo]

I don't have a fix for this to be fully cross-platform, but this is what I've done locally for running tests in the core package (just commenting so this shows up in issues search):

// in packages/core/package.json
"test": "cross-env TS_NODE_COMPILER_OPTIONS='{\"module\":\"commonjs\",\"target\":\"es5\"}' ava",

whereas currently it looks like:

"test": "cross-env TS_NODE_COMPILER_OPTIONS={\\\"module\\\":\\\"commonjs\\\",\\\"target\\\":\\\"es5\\\"} ava",

and gives this error when running tests:

SyntaxError: Unexpected token a in JSON at position 1
  parse (/your/path/here/jsonforms/node_modules/.pnpm/[email protected]_@[email protected][email protected]/node_modules/ts-node/src/util.ts:58:43)
  Object.<anonymous> (/your/path/here/jsonforms/node_modules/.pnpm/[email protected]_@[email protected][email protected]/node_modules/ts-node/src/index.ts:457:25)

[lucas-koehler]

@DrewHoo Thanks for the hints :) Your fix gave me an idea to see if these configs can be done in a platform independent way. Turns out they can (see #2171)