chore: remove backslash-escaping in Makefile errors & warnings (#972)
chore: remove backslash-escaping in Makefile errors & warnings (#972)

They're unnecessary, and actually cause the backslash to get printed.
resin-io/etcher,resin-io/herostratus,resin-io/etcher,resin-io/etcher,resin-io/resin-etcher,resin-io/etcher,resin-io/herostratus,resin-io/etcher,resin-io/resin-etcher