Update fetch content CMake example to point to correct tag

[DonMaEn]

The fetch content CMake example says based on the comment that it points to tag 1.0.1, however it points to an older tag. The older tag version would not build without warnings, however the newer version builds with no warnings. The tag should be 0af55ccecd98d4e5a8d1fad7de25ba429d60e863 I believe

On a side note, is the g-truc fork of this repo now the official GLM repo? I somehow ended up in the original repo and got confused. It might be appropriate to update the original repo with a notice of deprecation at the top of the readme.md or something.