[TF-M] TF-M v1.2.0 release

Hello,

TF-M project released version v1.2.0, tagged as TF-Mv1.2.0. This release has started using adopted semantic versioning as described in the release_process.rsthttps://git.trustedfirmware.org/TF-M/trusted-firmware-m.git/tree/docs/contributing/release_process.rst Please take a look into the release notes for the new features and changes.

Thanks to everyone who directly and indirectly contributed to this milestone.

Anton Komlev TF-M technical lead Arm Ltd.