Fix npm audits

[gcochard]

What does this Pull Request do?

Updates a bunch of deps to squelch npm audit warnings.

Where should the maintainers start when reviewing your request?

package.json

Is there any additional background context you'd like to provide?

npm audit now warns if packages have vulnerabilities. These vulns were in dev dependencies and generally apply to user-input handling code, but the deps needed updating anyway.

Are there any relevant issues?

No

Questions:

• Does this request add new dependencies to spectcl? No
• Does this request constitute a MAJOR change to spectcl's version? No

[coveralls]

Coverage remained the same at 96.567% when pulling 4b1a3fb on npm-audit-fixes into 5bf6a4d on master.

[gcochard]

All tests passing, coveralls still reporting. Merging.