Update dependency nconf to ^0.12.0

[renovate[bot]]

This PR contains the following updates:

Package	Change	Age	Adoption	Passing	Confidence
nconf	^0.11.4 -> ^0.12.0

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Release Notes

flatiron/nconf

### [`v0.12.0`](https://togithub.com/indexzero/nconf/releases/tag/v0.12.0) [Compare Source](https://togithub.com/flatiron/nconf/compare/v0.11.4...v0.12.0) Fixes: - Upgrade `async` to v3.x to resolve CVE-2021-43138 ([#​396](https://togithub.com/flatiron/nconf/issues/396)) ([@​mhamann](https://togithub.com/mhamann))

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