Update to 1.8.1

I just noticed the package is flagged Out of date. I managed to compile / install / run it successfully just by changing the following:

• pkgver from 1.7.1 to 1.8.1
• sha512sum to 18f996e56aa4de44c8f45d5ad051a07f2927f8115c76ecce9be9dfe0a59f3b5175a93de8442f384162cf406298833d9a364f2ca5f9a51797961505368fe5d3d5
• b2sum to 9e08d324602105a82c965c158b99c753f4815fd314453efa013157a3365fe882baea9bdf4a5943a7a8eabd33a4dca0e14a2ee1437256d522080199fd596f2169

It's not an issue per se, but just wanted to tell you here, in case it's easier for you to know it's a quick win. I'd be happy to submit a patch or contribute, not sure where to start.

Thanks you so much for all your efforts, dear maintainer! 🙏