Implementation of Deprecated DSS PubKey

[cchance27]

Not sure if your accepting PR's but I went ahead and implemented the SSH-DSS pubkey algorithm, tried to follow your pattern and naming conventions as best as I could.

Have tested it locally connecting to a local device that only supports DSS, as well as some other algorithms that are deprecated but already supported.

Implemented after running into it with #80

[HsuJv]

LGTM, thanks for the contribution,
But if you could help fix the CI warnings so that I can merge 'em into the main?

BRs.

Note:
ssh-dss should be added for both HostKeyAlgorithms & PubkeyAcceptedAlgorithms in this line

ssh-rs/.github/workflows/build.yml

Line 87 in 040bcf9

run: ssh-keygen -A && sed -i -E "s|(AuthorizedKeysFile).*|\1 %h/.ssh/authorized_keys|g" /etc/ssh/sshd_config && echo "HostKeyAlgorithms=+ssh-rsa" >> /etc/ssh/sshd_config && echo "PubkeyAcceptedAlgorithms=+ssh-rsa" >> /etc/ssh/sshd_config && echo "KexAlgorithms=+diffie-hellman-group14-sha1,diffie-hellman-group1-sha1" >> /etc/ssh/sshd_config && echo "Ciphers=+aes128-cbc,3des-cbc,aes192-cbc,aes256-cbc" >> /etc/ssh/sshd_config && sed -i -E "s/#?(ChallengeResponseAuthentication|PasswordAuthentication).*/\1 yes/g" /etc/ssh/sshd_config

[cchance27]

cleaned up the cargo fmt and clippy warnings, and adjusted the CI params should clear now.

[HsuJv]

Close #80

[HsuJv]

Seems we cannot simply configure the server to use ssh-dss like ssh-rsa, which looks strange.
I'll have another release when I manage to fix the CI issue.

BRs.

[HsuJv]

version 0.4.3 is now released

Thanks again for the contribution.