Add issue and PR metrics badges.

[JimiC]

No description provided.

[JimiC]

https://www.traviscistatus.com/
macOS builds are piling up due to maintenance.

[codecov]

Codecov Report

Merging #814 into master will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master     #814   +/-   ##
=======================================
  Coverage   92.75%   92.75%           
=======================================
  Files          38       38           
  Lines        1490     1490           
  Branches      111      111           
=======================================
  Hits         1382     1382           
  Misses         65       65           
  Partials       43       43

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 8631596...6747b94. Read the comment docs.