Bug: NPM aliases do not work

[rschristian]

This will fall over:

{
  "dependencies": {
    "react": "npm:@preact/compat"
  }
}

...as I naively merge key & val into a string with an @ separator:

deptree/src/index.jsx

Line 47 in 3f4c8f9

.map(([key, value]) => `${key}@${value}`))