update version pinning for new platform release

lib/leap_cli/version.rb

 module LeapCli
   unless defined?(LeapCli::VERSION)
-    VERSION = '1.8'
-    COMPATIBLE_PLATFORM_VERSION = '0.8'..'0.99'
+    VERSION = '1.8.1'
+    COMPATIBLE_PLATFORM_VERSION = '0.8'..'0.8.99'
     SUMMARY = 'Command line interface to the LEAP platform'
     DESCRIPTION = 'The command "leap" can be used to manage a bevy of servers running the LEAP platform from the comfort of your own home.'
     LOAD_PATHS = ['lib', 'vendor/certificate_authority/lib', 'vendor/rsync_command/lib']