Fixes #7383 by adding cppstd to QNX QCC in settings and #7426 by adding version 8.3

[mjvankampen]

Changelog: Bugfix: cppstd was missing in settings.yml for the qcc compiler and updates to 8.3.
Docs: Omit

I am not sure though if I also need to update the documents

Close #7383
Close #7426

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[memsharded]

Thanks for contributing this!

Yeah, I think we are good without docs. For this cases you can put:

Docs: Omit

In the comment.

If the PR closes open issues, you can also put it as:

Close #7383
Close #7426

So when the PR is merged, those issues are automatically closed.

Many thanks!