Can't install on npm 7

[falsandtru]

npm 7 has a breaking change. Can you fix?

$ npm i
npm ERR! code ERESOLVE
npm ERR! ERESOLVE unable to resolve dependency tree
npm ERR!
npm ERR! While resolving: spica@0.0.433
npm ERR! Found: typescript@4.3.0-dev.20210213
npm ERR! node_modules/typescript
npm ERR!   dev typescript@"4.3.0-dev.20210213" from the root project
npm ERR!
npm ERR! Could not resolve dependency:
npm ERR! peer typescript@">= 2.8" from tsify@5.0.2
npm ERR! node_modules/tsify
npm ERR!   dev tsify@"^5.0.2" from the root project
npm ERR!
npm ERR! Fix the upstream dependency conflict, or retry
npm ERR! this command with --force, or --legacy-peer-deps
npm ERR! to accept an incorrect (and potentially broken) dependency resolution.

npm/cli#2695