Incorrect remove alternative example in README.md

[karlding]

For the LWRP remove alternative example:

alternatives 'python install 3' do
  link_name 'python'
  path '/usr/bin/python3'
  priority 101
  action :install
end

It looks like the LWRP install alternative example was copied over. I assume the example needs to be corrected, and action should be :remove?

[vkhatri]

@karlding 👍

Updated README.