Update bupstash entry

[lgommans]

References:

• compression,dedup,encrypted https://bupstash.io/doc/guides/Getting%20Started.html
• incremental was already there, and it follows from dedup I think? Not sure why this is separate but I'll just leave it.
• rust https://github.com/andrewchambers/bupstash "Bupstash is written in a memory safe language to dramatically reduce the attack surface over the network" + GitHub language stats. Though there is also a lot of C code according to said language stats.
• authenticated https://github.com/andrewchambers/bupstash/blob/master/doc/technical_overview.md "We use libsodium cryptobox to encrypt each data chunk." -> https://doc.libsodium.org/public-key_cryptography/authenticated_encryption

For the order of the tags, I tried to look at other entries but it doesn't seem to be ordered in a particular way if I saw it correctly.

[cfcs]

@lgommans thank you for the PR and the sources/references, excellent!