feat(gatsby-plugin-google-tagmanager): Allow to place the GTM script …

[NoriSte]

…at the end of the tag

Description

I added one more option to the gatsby-plugin-google-tagmanager plugin to allow adding the GTM script in the head (by default, as it is now) or append it to the body (to make it non-blocking).

[sidharthachatterjee]

Thank you for adding this @NoriSte 👍

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Thanks again!

[NoriSte]

Is the NPM release of the plugin automatic? Do you know when it could happen? To know when I can discard my changes and re-download the official one. 😊

[sidharthachatterjee]

@NoriSte Releases are manual at the moment and requires one of us from the core team to publish.

I've reverted this in #13424 because @wardpeet correctly pointed out that since the script is always added async, this doesn't really have any impact and hence it's best that we don't add another option.

Nonetheless, thank you again for your contribution and sorry for the confusion!

[NoriSte]

I need some more investigations because I got (obviously as it seems) wrong feedbacks from my first tests. I'll let you know as soon as I find out something more.
Anyway: don't worry and sorry!