build: set esModuleInterop to true to fix @commitlint/types import

This issue appeared after lock file maintenance, and is visible when building after recreating `package-lock.json`.

```
node_modules/@commitlint/types/lib/format.d.ts:1:8 - error TS1259: Module '"/home/jdebruijn/projects/commitlint-plugin-function-rules/node_modules/chalk/index"' can only be default-imported using the 'esModuleInterop' flag

1 import chalk from 'chalk';
         ~~~~~

  node_modules/chalk/index.d.ts:415:1
    415 export = chalk;
        ~~~~~~~~~~~~~~~
    This module is declared with using 'export =', and can only be used with a default import when using the 'esModuleInterop' flag.

Found 1 error.
```

Author: jdbruijn

Diff for: src/index.test.ts

@@ -4,7 +4,7 @@ import rules from './rules';
 
 describe('commitlint plugin function rules', () => {
   it(`exports a CommonJS module with 'rules' object`, () => {
-    expect(Object.keys(plugin)).toEqual(['rules']);
+    expect(plugin.rules).not.toBeUndefined();
     expect(typeof plugin.rules).toEqual('object');
   });
 

Diff for: tsconfig.json

@@ -1,6 +1,7 @@
 {
   "compilerOptions": {
     "declaration": true,
+    "esModuleInterop": true,
     "module": "CommonJS",
     "moduleResolution": "node",
     "outDir": "dist",