package.json: bump karma version
package.json: bump karma version

A newer version of fsevents, pulled in as a recursive dependency of
karma, is needed to build against newer versions of node.

artefactual-labs/appraisal-tab,eckardm/appraisal-tab,artefactual-labs/appraisal-tab,eckardm/appraisal-tab,djpillen/appraisal-tab,djpillen/appraisal-tab