Fix json import

[ekohilas]

Reopening of #1422

In Node 18.18, the following error occurs:

npx --yes gitlab-ci-local@latest                                                                                                                                                 
file:///Users/username/.npm/_npx/3f18f2096def1b34/node_modules/gitlab-ci-local/src/index.js:13
import packageJson from "../package.json" with { type: "json" };
                                          ^^^^

SyntaxError: Unexpected token 'with'
    at ESMLoader.moduleStrategy (node:internal/modules/esm/translators:119:18)
    at ESMLoader.moduleProvider (node:internal/modules/esm/loader:468:14)
    at async link (node:internal/modules/esm/module_job:68:21)

Node.js v18.18.2

This PR fixes the issue by converting json imports to instead use readfilesync and JSON.parse instead, which makes it more explicit and avoids this error.

This fix allows users who may otherwise not be able to update to Node v18.20 overnight to continue using this tool.

Thanks again!

[firecow]

@ANGkeith You sure we wanna keep node 18 support?

[ANGkeith]

hmm not really, but at least for now, does'nt seem like there is too much incompatibility.