Fix lockfile with `npm install`

[wipfli]

CI is currently broken I think because the lockfile is bad. At least, CI failed in #68 with some indication that the lockfile is bad...

• [ ] briefly describe the changes in this PR
• [ ] write tests for all new functionality
• [ ] run npm run docs and commit changes to API.md
• [ ] update CHANGELOG.md with changes under main heading before merging

[wipfli]

Hm, strange that it is still broken. npm ci works locally...