Update to 2.4.2
    
    - New upstream release 2.4.2
      - Fix exploit (GH#1283, CVE-2018-1000805) in Paramiko’s server mode (not
        client mode) where hostile clients could trick the server into thinking
        they were authenticated without actually submitting valid authentication
      - Modify protocol message handling such that Transport does not respond to
        MSG_UNIMPLEMENTED with its own MSG_UNIMPLEMENTED; this behavior probably
        didn’t cause any outright errors, but it doesn’t seem to conform to the
        RFCs and could cause (non-infinite) feedback loops in some scenarios
        (usually those involving Paramiko on both ends)
      - Add *.pub files to the MANIFEST so distributed source packages contain
        some necessary test assets (GH#1262)
    - Test suite now requires mock ≥ 2.0.0