[suggestion] writeHash should use default parameter instead of bind

[kinland]

The original writeHash method takes an optional string for the hash.

However, the method that gets returned is writeHash.bind(null, result.hash)

As a result, as a workaround for #16 , I'm unable to write a custom hash.

My suggestion is to move the writeHash method to just below the const result = and change it to

    const writeHash = (hash: string | undefined = result.hash) =>
        hash && fs.writeFileSync(packageHashPath, hash, {});

This would allow me to use a concatenated hash for multiple files, like so:

/** @type {import('package-changed/types')} */
const { isPackageChanged } = require('package-changed');

/** @type {import('child_process')} */
const { execSync } = require('node:child_process');

(async () => {
    const { oldHash, hash: rootHash, writeHash } = await isPackageChanged({ noHashFile: true });
    const { hash: nextjsHash } = await isPackageChanged({ noHashFile: true, cwd: './nextjs' });

    const newHash = `${rootHash}${nextjsHash}`;

    if (newHash !== oldHash) {
        console.log("Package changed. Running 'rm -f .eslintcache && pnpm install'.");
        // dependencies in a package.json have changed since last run
        execSync('rm -f .eslintcache');
        execSync('pnpm install');

        writeHash(newHash);
    }
})();

I will open a PR for this shortly.