Fix release note for PR 14444 to 21.3

[hafizrahman]

After #14444 was already merged, @selanthiraiyan realized that its release note was set to 21.2. This PR moves the note to 21.3.

To test:
Nothing, just ensure it's in the right spot now.

[hichamboushaba]

LGTM

[wpmobilebot]

📲 You can test the changes from this Pull Request in WooCommerce iOS by scanning the QR code below to install the corresponding build.

	App Name	WooCommerce iOS
	Build Number	pr14521-6a7320c
	Version	21.2
	Bundle ID	com.automattic.alpha.woocommerce
	Commit	6a7320c
	App Center Build	WooCommerce - Prototype Builds #11770

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