Add support for HS384, HS512, RS384, RS512, and ES384

[EliseZeroTwo]

This MR:

• Updates dependencies
• Adds support for HS384, HS512, RS384, RS512, and ES384 (key generation for ES384 is missing due to the arithmatic in the P384 crate being broken)
• Fixes a bug when converting RSA keys to jsonwebtoken::DecodingKey as they weren't turned into public keys before PEM encoding

I can split this into 3 seperate merge requests if needed.

[XLPhere]

Otherwise this looks useful to me, any chance of this getting merged? @nhynes

[EliseZeroTwo]

Otherwise this looks useful to me, any chance of this getting merged? @nhynes

You can also just use my fork if you want, I don't plan on deleting it even after it's merged due to the usage of the fork elsewhere