ssh: fix parsing of ed25519 keys When attempting to use ed25519 SSH keys, parse_pub_key() failed with: SshKeyParseError: Incorrect SSH key - base64 part is not 'ssh-ed25519' as claimed but 'ssh-ed25519' The problem was the hardcoding of the string length of the key type -- 7 or '\x07' -- which fits ssh-rsa and ssh-dss but not ssh-ed25519. (Fix was simplified by Mads Kiilerich.)

# requirements.txt file for use as "pip install -r requirements.txt" as a
# readthedocs compatible alternative to "pip install -e ." which is a working
# alternative to "setup.py develop" which doesn't work with Mercurial 3.7
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