Update badges

[KineticTheory]

Background

• Remove Travis badge and replace it with a GitHub Action badge.
• https://docs.github.com/en/actions/managing-workflow-runs/adding-a-workflow-status-badge#using-the-branch-parameter

Status

• Reference:
  • Pre-Merge Code Review
  • CDash Status
• Checks
  • Travis/Appveyor CI checks pass
  • Code coverage does not decrease
  • Valgrind test passes
  • Toss3 checks pass
  • Trinitite checks pass
  • Code reviewed/approved, sufficient DbC checks, testing, documentation

[codecov]

Codecov Report

Merging #1080 (dbe73ef) into develop (560993e) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           develop   #1080   +/-   ##
=======================================
  Coverage     88.6%   88.6%           
=======================================
  Files          374     374           
  Lines        18579   18579           
=======================================
  Hits         16479   16479           
  Misses        2100    2100