use bundler 1.7 because it would require dropping ruby versions currently supported
use bundler 1.7 because it would require dropping ruby versions currently supported

We will shortly remove all EOL versions.

Signed-off-by: Ben Abrams <b1c1d8736f20db3fb6c1c66bb1455ed43909f0d8@benabrams.it>

sensu-plugins/sensu-plugins-windows