Adding a Count function

[theouteredge]

Just adding a simple Count function which allows you to count how many items in a slice match the predicate you specify

[codecov[bot]]

Codecov Report

Merging #34 (b1cb789) into main (0bc3a54) will increase coverage by 0.02%. The diff coverage is 100.00%.

@@            Coverage Diff             @@
##             main      #34      +/-   ##
==========================================
+ Coverage   99.19%   99.21%   +0.02%     
==========================================
  Files          29       30       +1     
  Lines         247      254       +7     
==========================================
+ Hits          245      252       +7     
  Misses          2        2              

Flag	Coverage Δ
unittests	99.21% <100.00%> (+0.02%)	:arrow_up:

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
count.go	100.00% <100.00%> (ø)

:mega: We’re building smart automated test selection to slash your CI/CD build times. Learn more