Add support for ed25519 keys

[invidian]

Right now using them throws an error:

Error: getting recipients: decoding public key #0: parsing public key: openpgp: unsupported feature: public key type: 22

This can be done by migrating to https://gopenpgp.org/, https://pkg.go.dev/github.com/ProtonMail/gopenpgp/v2/crypto

[bmaximuml]

Hi @invidian, this feature would be very useful to me! We use this provider at my org, and we're all using RSA keys as a result. Would be great to be able to start using ed25519

Thanks

[invidian]

Hi @invidian, this feature would be very useful to me! We use this provider at my org, and we're all using RSA keys as a result. Would be great to be able to start using ed25519

Thanks for the feedback. Unfortunately, I don't think I will have time to implement this, although I could also make use of this feature. I would accept a contribution though and I'm happy to make a new release then.

I hope the SDK libraries are not too old for newest Terraform version though. I'm guessing gpg_encrypted_message resource could actually become a function too, now that Terraform supports providers exporting custom functions, since there is nothing stateful IIUC in the GPG messages.