Update README.md

[astrolamb]

Updated README for apple silicon installation. @AaronDJohnson can you review?

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 71.55%. Comparing base (80b70cc) to head (9e049e0).
Report is 102 commits behind head on master.

Additional details and impacted files

@@             Coverage Diff             @@
##           master     #410       +/-   ##
===========================================
- Coverage   85.33%   71.55%   -13.79%     
===========================================
  Files          13       13               
  Lines        3158     3245       +87     
===========================================
- Hits         2695     2322      -373     
- Misses        463      923      +460     

see 3 files with indirect coverage changes

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[vhaasteren]

Hi @astrolamb, can you merge dev or master, and push your branch?

Then, perhaps adjust the text so that it reflects the new situation about libstempo and PINT not being required? Just say that, in the case that these packages are desired on arm, we must do...

Thanks!

[astrolamb]

@vhaasteren done