Adding check on epiworldR

[gvegayon]

This pull request includes significant updates to the continuous integration (CI) workflow configuration in the .github/workflows/ci.yml file. The changes primarily focus on specifying branch triggers for CI actions and adding new jobs to test the epiworldR package.

Key changes include:

CI Workflow Configuration:

• Updated the on section to trigger CI actions only on pushes to the master branch and on pull requests.

New Jobs for Testing epiworldR:

• Added a new job test-epiworld-r to run tests for the epiworldR package using the rocker/r2u:latest container. This job installs necessary R packages and dependencies, builds the package, and runs checks.
• Added another job test-epiworld-r-valgrind similar to test-epiworld-r, but with additional steps to install valgrind and run the package checks using valgrind for memory analysis.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 83.96%. Comparing base (d177940) to head (9ee53cd).
Report is 1 commits behind head on master.

Additional details and impacted files

@@           Coverage Diff           @@
##           master      #33   +/-   ##
=======================================
  Coverage   83.96%   83.96%           
=======================================
  Files          42       42           
  Lines        2763     2763           
=======================================
  Hits         2320     2320           
  Misses        443      443           

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🚨 Try these New Features:

• Flaky Tests Detection - Detect and resolve failed and flaky tests

[apulsipher]

lgtm