add brew install to readme and spot os roadmap

[bwagner5]

Issue #, if available:
N/A

Description of changes:

• Brew install instructions
• Spot Roadmap to Communication section

By submitting this pull request, I confirm that you can use, modify, copy, and redistribute this contribution, under the terms of your choice.

[brycahta]

LGTM

[codecov-commenter]

Codecov Report

Merging #43 into master will increase coverage by 0.22%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master      #43      +/-   ##
==========================================
+ Coverage   88.38%   88.61%   +0.22%     
==========================================
  Files           9        9              
  Lines        1068     1063       -5     
==========================================
- Hits          944      942       -2     
+ Misses         88       87       -1     
+ Partials       36       34       -2     

Impacted Files	Coverage Δ
pkg/selector/selector.go	82.89% <0.00%> (+0.92%)	⬆️

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