Change dependency check

Now that the [corresponding PR in aiida-core](aiidateam/aiida-core#3787) has been merged, we know that 1.6 still has the old syntax, and the new changes will appear in 2.x only so I suggest to change this check

aiida_sshonly/transports/sshonly.py

@@ -19,7 +19,7 @@
 
 import aiida
 from distutils.version import StrictVersion  # pylint: disable=no-name-in-module,import-error
-if aiida.get_strict_version() < StrictVersion('1.6.0'):
+if aiida.get_strict_version() < StrictVersion('2.0.0'):
   from .ssh import SshTransport
 else:
   from aiida.transports.plugins.ssh import SshTransport