Update dependency node-sass to v5

[renovate[bot]]

This PR contains the following updates:

Package	Type	Update	Change
node-sass	devDependencies	major	4.14.1 -> 5.0.0

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Release Notes

sass/node-sass

### [`v5.0.0`](https://togithub.com/sass/node-sass/releases/v5.0.0) [Compare Source](https://togithub.com/sass/node-sass/compare/v4.14.1...v5.0.0) ##### Breaking changes - Only support LTS and current Node versions ([@​nschonni](https://togithub.com/nschonni)) - Remove deprecated process.sass API ([@​xzyfer](https://togithub.com/xzyfer), [#​2986](https://togithub.com/sass/node-sass/issues/2986)) ##### Features - Add support for Node 15 - New node-gyp version that supports building with Python 3 ##### Community - More inclusive documentation ([@​rgeerts](https://togithub.com/rgeerts), [#​2944](https://togithub.com/sass/node-sass/issues/2944)) - Enabled dependabot ([@​nschonni](https://togithub.com/nschonni)) - Improve release automation ([@​nschonni](https://togithub.com/nschonni)) ##### Fixes - Bumped many dependencies ([@​nschonni](https://togithub.com/nschonni)) #### Supported Environments | OS | Architecture | Node | | ------------ | ------------ | -------------- | | Windows | x86 & x64 | 10, 12, 14, 15 | | OSX | x64 | 10, 12, 14, 15 | | Linux\* | x64 | 10, 12, 14, 15 | | Alpine Linux | x64 | 10, 12, 14, 15 | | FreeBSD | i386 amd64 | 10, 12, 13 | \*Linux support refers to major distributions like Ubuntu, and Debian

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