feat: fix the peer dep test; update all deps to latest

BREAKING CHANGE:
- Several ESLint plugins received major updates.
- ESLint versions below v7.15.0 are no longer supported.

CONTRIBUTING.md

@@ -32,7 +32,7 @@ This project adheres to the American Express [Code of Conduct](./CODE_OF_CONDUCT
 3. Install the dependencies by running
 
     ```bash
-    $ cd npm install
+    $ npm install
     ```
 
 4. You can now run any of these scripts from the root folder.

__tests__/package.spec.js

@@ -22,7 +22,7 @@ describe('package.json', () => {
     expect.assertions(2);
     // ex:
     // npm ERR! peer dep missing: eslint@<2.3.0, required by babel-eslint@5.0.4
-    const { stdout, stderr } = exec('npm ls', {
+    const { stdout, stderr } = await exec('npm ls', {
       cwd: path.resolve(__dirname, '../'),
     });
     // if there are no complaints from npm, stdout is null