Sync docs from Discourse (#243)

Sync charm docs from https://discourse.charmhub.io

Co-authored-by: GitHub Actions <41898282+github-actions[bot]@users.noreply.github.com>

Author: github-actions[bot]

docs/reference/r-system-requirements.md

@@ -16,7 +16,7 @@ Make sure your machine meets the following requirements:
 
 ## Supported architectures
 
-The charm is based on SNAP "[charmed-mysql](https://snapcraft.io/charmed-mysql)", which is currently available for `amd64` only! The architecture `arm64` support is planned. Please [contact us](/t/12323) if you are interested in new architecture!
+The charm is based on SNAP "[charmed-mysql](https://snapcraft.io/charmed-mysql)", which is currently available for `amd64` and `arm64` only! Please [contact us](/t/12323) if you are interested in new architecture!
 
 <a name="mysql-gr-limits"></a>
 ## Charmed MySQL requirements