DKIM: `i=` tag may not match in some auto-generated messages

[ikedas]

Version

6.2.72 or earlier.

Installation method

Any.

Expected behavior

In the message originated by Sympa, the identity (i= tag) in DKIM signature should match the address in the From: field.

Actual behavior

In the message originated by <sympa> address, i= tag does not match From: field.

...
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed; d=sympa.community; h=
	content-transfer-encoding:content-type:date:from:message-id
	:mime-version:subject:to; s=k2022w50; i=
	[email protected]; bh=...
Message-Id: <[email protected]>
Date: Fri, 15 Sep 2023 02:27:08 +0000
From: "SYMPA" <[email protected]>
MIME-Version: 1.0
Content-Type: text/plain; charset="US-ASCII"
Content-Transfer-Encoding: 7BIT
Auto-Submitted: auto-generated
To: ...
Subject: List translate: Failed to change member email address
X-Mailer: Sympa 6.2.72

...

Steps to reproduce

Enable DKIM signing and receive any auto-response messages from Sympa.

Additional information

I'm preparing a PR.