remove no longer existing --experimental-json-modules module

ref. nodejs/node@c3f7251

Author: shinnn

README.md

@@ -63,7 +63,6 @@ If the provided JavaScript path ends with `.mjs`,
 
 * [ECMAScript module mode](https://nodejs.org/api/esm.html) is automatically [enabled](https://nodejs.org/api/esm.html#esm_enabling).
 * [`--es-module-specifier-resolution`](https://nodejs.org/api/esm.html#esm_customizing_esm_specifier_resolution_algorithm) is automatically set to `node`.
-* [Experimental JSON modules support](https://nodejs.org/api/esm.html#esm_experimental_json_modules) is automatically enabled.
 
 #### Reporters
 

index.js

@@ -72,7 +72,6 @@ const codecovBashPath = process.platform === 'win32' ? join(cwd, 'coverage', Mat
 				...ext === 'mjs' ? [
 					'--experimental-modules',
 					'--es-module-specifier-resolution=node',
-					'--experimental-json-modules',
 					'--no-warnings'
 				] : [],
 				entryPath