update check_with_errors for new devtools

[infotroph]

Fixes #2173

devtools::check now defaults to exiting with an error on any warning or error from R CMD check, so we need to specify error="never" so that the check_with_errors script can finish (Otherwise it Also, an unrelated issue will falsely report success with 0 warnings and 0 notes).

Note that this means check_with_errors.R is now redundant for its original purpose (which was basically to provide the behavior we could now get from devtools::check(..., error_on="error")), but I propose we keep it around and use it to start promoting specific warnings to errors as a path toward finishing #1949.

Description

Motivation and Context

Review Time Estimate

• Immediately
• Within one week
• When possible

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist:

• My change requires a change to the documentation.
• I have updated the CHANGELOG.md.
• I have updated the documentation accordingly.
• I have read the CONTRIBUTING document.
• I have added tests to cover my changes.
• All new and existing tests passed.

[infotroph]

This appears to be working -- ready for review now.