Mac m1 support

[Nickjgniklu]

Getting and error like this on Mac M1

[warning] The on_load function for module prometheus_process_collector returned:
{:error,
 {:load_failed,
  'Failed to load NIF library: 
...
prometheus_process_collector.so\' (mach-o file, but is an incompatible architecture (have \'x86_64\', need \'arm64\'))\''}}

I was able to build this library with rebar3 on my M1 and copy and pasted it over the Mac x86_64 files in my elixir project to test if it works at all. It appears to work.