fix: add local definition of isPrivateIp

[wemeetagain]

Description

Use local defintion of isPrivateIp instead of private-ip package
This should reduce bundle size and remove another commonjs sub-dependency (ipaddr.js)

Change checklist

• I have performed a self-review of my own code
• I have made corresponding changes to the documentation if necessary (this includes comments as well)
• I have added tests that prove my fix is effective or that my feature works

[maschad]

You should verify that this decreases the bundle size and update the limits as well for each package so that this change is worthwhile.

[SgtPooki]

is this a copy of https://github.com/frenchbread/private-ip/blob/master/test.js ?

[wemeetagain]

yes, also the source is a modified version of https://github.com/frenchbread/private-ip/blob/master/src/index.ts

[wemeetagain]

You should verify that this decreases the bundle size

Its guaranteed to be smaller because its the same code, but with two fewer dependencies.

[achingbrain]

@wemeetagain LGTM but CI is failing, could you take a look please?

[wemeetagain]

@achingbrain ready for re-review