Set up r-lib R CMD check action

[dan-knight]

This is a template for UCLA-CDS R package developers to create a github pull request template. Things should be adjusted for individual package including:

1. additional checklist items sepecific to the package
2. a description of how testing is expected to be done
3. a template list or table for testing results
4. additional notes wrapped in <!--- ---> (or <!-- --> for inline comments) that help PR submitters to fill in.
5. delete this block of instructional text.

• I have read the code review guidelines and the code review best practice on GitHub check-list.

• The name of the branch is meaningful and well formatted following the standards, using [AD_username (or 5 letters of AD if AD is too long)-[brief_description_of_branch].

• I have set up or verified the branch protection rule following the github standards before opening this pull request.

• I have added the changes included in this pull request to NEWS under the next release version or unreleased, and updated the date.

• I have updated the version number in metadata.yaml and DESCRIPTION.

• Both R CMD build and R CMD check run successfully.

Closes #...

Testing Results

Case 1

input code
output

Case 2

input code
output

[WuSelina]

looks good to me!