feat: export normalizePrivateKey

[SergeyVolynkin]

Hi @paulmillr, thank you for the effort you put into this library!

Would it be possible to export normPrivKey on the npm package?
We plan to use it for account derivation logic with grindKey which does not always result in a padded private key.

[paulmillr]

Can you export it as normalizePrivateKey?

[SergeyVolynkin]

@paulmillr renamed the exported function to normalizePrivateKey in e9e1bb7

Please let me know if you'd prefer the export alias solution instead:

export { normPrivateKey as normalizePrivateKey };
function normPrivateKey(privKey: Hex): string {
  return u.bytesToHex(ensureBytes(privKey)).padStart(64, '0');
}

[paulmillr]

Please also add some kind of test. It can be basic, like, 1-3 lines of code.

And fix failing CI.

[SergeyVolynkin]

Thank you @paulmillr

1. Added test
2. Opened fix: resolve TS warning after upgrade to "typescript": "5.5.2" #11 to fix CI, as it fails for unrelated change (started to fail after TS upgrade to v5.5