package.json: fix dependency conflict

[Ferk]

There's a dependency conflict that causes an error when attempting to run npm install.

I had to set the eslint version to "^5.0.0" for it to work. This PR fixes it.

Below the log output:

# npm resolution error report

While resolving: @typescript-eslint/[email protected]
Found: [email protected]
node_modules/eslint
  dev eslint@"6.1.0" from the root project
  peer eslint@"*" from @typescript-eslint/[email protected]
  node_modules/@typescript-eslint/experimental-utils
    @typescript-eslint/experimental-utils@"1.13.0" from @typescript-eslint/[email protected]
    node_modules/@typescript-eslint/eslint-plugin
      dev @typescript-eslint/eslint-plugin@"1.13.0" from the root project
    @typescript-eslint/experimental-utils@"1.13.0" from @typescript-eslint/[email protected]
    node_modules/@typescript-eslint/parser
      dev @typescript-eslint/parser@"1.13.0" from the root project
      peer @typescript-eslint/parser@"^1.9.0" from @typescript-eslint/[email protected]
      node_modules/@typescript-eslint/eslint-plugin
        dev @typescript-eslint/eslint-plugin@"1.13.0" from the root project
  peer eslint@"^3.0.0 || ^4.0.0 || ^5.0.0 || ^6.0.0" from [email protected]
  node_modules/eslint-plugin-react
    dev eslint-plugin-react@"7.16.0" from the root project

Could not resolve dependency:
peer eslint@"^5.0.0" from @typescript-eslint/[email protected]
node_modules/@typescript-eslint/eslint-plugin
  dev @typescript-eslint/eslint-plugin@"1.13.0" from the root project

Conflicting peer dependency: [email protected]
node_modules/eslint
  peer eslint@"^5.0.0" from @typescript-eslint/[email protected]
  node_modules/@typescript-eslint/eslint-plugin
    dev @typescript-eslint/eslint-plugin@"1.13.0" from the root project

Fix the upstream dependency conflict, or retry
this command with --force or --legacy-peer-deps
to accept an incorrect (and potentially broken) dependency resolution.