Batch npm fetch

• I have searched for similar issues
• I am using the latest version of npm-check-updates
• I am using node >= 10.17

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Steps to Reproduce

Run ncu with >100 dependencies and a slow internet connection.

Current Behavior

It's slow.

Expected Behavior

It's fast.

Suggested solution

Ask npm to expose a route where one can query for more than one package at a time. It could even explicitly be an updates available route that only replies with a list of updates given current version, not with a list of last available versions. They will have to put limits on this route like maximum payload (ncu resolves wildcards locally), but on average I think it would lighten the load on their side and make it faster for us.