Update vulnerable dependencies from npm audit report

[helen-m-lin]

Describe the bug

• There are currently 19 vulnerabilities (1 critical, 8 high, 10 moderate) shown from running npm audit
• There is overlap with GitHub Dependabot alerts, tracked in Resolve GitHub Dependabot vulnerability alerts #137.
• 5 of 19 vulnerabilities can be fixed using npm audit fix, the remainder require investigation.

To Reproduce
Steps to reproduce the behavior:

1. Clone the repo and check out dev branch
2. Run npm audit
3. Review security vulnerabilities

Expected behavior
All vulnerabilities should be resolved.

[helen-m-lin]

As of Apr 16, there were 9 vulnerabilities from npm audit --production and 21 from general report.

These are addressed in PR #168. All from prod report are addressed. Remaining issues for devDependencies can be ignored (
see previous PR #33 and facebook/create-react-app#11174)