DEVDOCS-5811: [update] for webhook security (#751)

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# [DEVDOCS-5811]


## What changed?
Updating the security information as the requirements for this ticket
changed and never were updated in the docs

## Release notes draft

bug Fix
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language. Don't be too technical. Explain how the change will benefit
the merchant and link to the feature.

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* The newly-released [X feature] is now available to use. Now, you’ll be
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* We're happy to announce [X feature], which can help you [perform Y
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* [X feature] helps you to create [Y response] using the [Z query
parameter]. Now, you can deliver [ex, localized shopping experiences for
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* Fixed a bug in the [X endpoint]. Now the [Y field] will appear when
you click [Z option]. -->
* 

## Anything else?
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ping {names}


[DEVDOCS-5811]:
https://bigcommercecloud.atlassian.net/browse/DEVDOCS-5811?atlOrigin=eyJpIjoiNWRkNTljNzYxNjVmNDY3MDlhMDU5Y2ZhYzA5YTRkZjUiLCJwIjoiZ2l0aHViLWNvbS1KU1cifQ

docs/integrations/webhooks/https-webhook-overview.mdx

@@ -193,7 +193,8 @@ After the final retry attempt (cumulatively **48 hours** after the first deliver
 
 To ensure webhook callback requests are secure, BigCommerce takes the following precautions:
 
-* Create webhook requests to accept an optional header object in every HTTP webhook, which you can use to authenticate callback requests. 
+* Create webhook requests to accept a header object in every HTTP webhook, which you can use to authenticate callback requests. 
+* We advise merchants to use libraries provided by [Standard Webhook](https://github.com/standard-webhooks/standard-webhooks/tree/main/libraries) to verify the legitimacy of the events. 
 * A timestamp is used to protect against replay attacks.
 * We recommend validating the signature and timestamp before processing any webhook event.