Pronto doesn't seem to compare files if they only changed file mode

[renatolond]

Hi! Thanks for your work in pronto :)

rubocop has a check for executables files without the right permission:

run:1:1: W: Lint/ScriptPermission: Script file run doesn't have execute permission.
#!/usr/bin/env ruby
^^^^^^^^^^^^^^^^^^^

1 file inspected, 1 offense detected, 1 offense auto-correctable

However, if I change the file mode, it seems pronto does not run rubocop on this file:

diff --git a/run b/run
old mode 100755
new mode 100644

[ashkulz]

@renatolond happy to accept PRs which fix this -- I suspect the bug is in this file.