Non-UTC DateTime format for Push event

Hello Community.
I’m having an issue with datetime format for GitHub events delivered for a webhook
For my repository, I configured a to receive the push event.
When I check the Recent Deliveries, there is this message.

Request URL: https://*..com:
Request method: POST
Accept: /
content-type: application/json
User-Agent: GitHub-Hookshot/d696b2a
X-GitHub-Delivery: bfc60e00-e7a6-11ea-82fe-fd8d904b960b
X-GitHub-Event: push
X-Hub-Signature: sha1=e8ed2ba85a5586d10a6767e98d07add4600833f5

The issue is that for the property timestamp, it is showing (at Recent Deliveries section) one value, however, the sent message is with other value.

Value from https://github.com///settings/hooks/***
“commits”: [{

“timestamp”: “2020-08-26T11:16:23-03:00”,

],

Value delivered at my server:
“commits”: [{

“timestamp”:“2020-08-26T14:16:23+00:00”,

],

From datetime value perspective, both are equals, however, from message string data used to create the signature, they are different.
The signature provided by GitHub is sha1=e8ed2ba85a5586d10a6767e98d07add4600833f5, this is valid for “timestamp”: “2020-08-26T11:16:23-03:00”. But is invalid for the payload sent to my sever “timestamp”:“2020-08-26T14:16:23+00:00”.

This is pretty much forcing me to not secure my endpoint.
Can you help me? Can we use UTC datetime format?

BTW, I’m from Brazil and the timezone here is GTM -03:00.

Best Regards

Guilherme Moschen