Add canonical url to layout

[halivert]

If canonicalUrl is found on the post, then it will be used for meta tag canonical.

[vercel]

@halivert is attempting to deploy a commit to the midudev pro Team on Vercel.

A member of the Team first needs to authorize it.

[midudev]

Thanks @halivert for the PR. For now, I'm not using the canonicalUrl param so I think this wouldn't be needed! But thanks anyway! 🤗

[halivert]

Great, the idea was to use it when someone else creates a mirror post from his/her blog in yours
anyways, thank you 😌