Webhook validator urlRegex doesnot contain '_'

[c7h12]

Describe the bug
The urlRegex in webhookvalidator can not match '_';

https://github.com/strapi/strapi/blob/master/packages/strapi-admin/controllers/Webhooks.js#L14

Steps to reproduce the behavior

1. settings/webhooks/add new webhook
   2.type 'http://ab_cd.test.com" as url
2. fill other fields
3. submit
4. "An error occurred"

Expected behavior
"_" is a legal charactor in host.

Screenshots
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Code snippets
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https://github.com/strapi/strapi/blob/master/packages/strapi-admin/controllers/Webhooks.js#L14

const urlRegex = /^(?:([a-z0-9+.-]+):\/\/)(?:\S+(?::\S*)?@)?(?:(?:[1-9]\d?|1\d\d|2[01]\d|22[0-3])(?:\.(?:1?\d{1,2}|2[0-4]\d|25[0-5])){2}(?:\.(?:[1-9]\d?|1\d\d|2[0-4]\d|25[0-4]))|(?:(?:[a-z\u00a1-\uffff0-9]-*)*[a-z\u00a1-\uffff0-9]+)(?:\.(?:[a-z\u00a1-\uffff0-9]-*)*[a-z\u00a1-\uffff0-9]+)*\.?)(?::\d{2,5})?(?:[/?#]\S*)?$/;

System

• Node.js version: v12.16.1
• NPM version: 6.13.4
• Strapi version: 3.0.0-beta.19.3
• Database: mysql 5.7
• Operating system: macos

[lauriejim]

Hello @c7h12 !
Thank you for reporting this issue.
Can you please submit a PR, thank you.

[msimmer]

I'd like to take this on if it's still open