Highlight PATCH versions can be used to upgrade

Signed-off-by: Hidde Beydals <hello@hidde.co>
Signed-off-by: jonathan-innis <jonathan.innis.ji@gmail.com>

docs/guides/installation.md

@@ -512,6 +512,10 @@ flux create helmrelease nginx \
 
 ## Upgrade
 
+!!! note "Patch versions"
+    It is safe and advised to use the latest PATCH version when upgrading to a
+    new MINOR version.
+
 Update Flux CLI to the latest release with `brew upgrade fluxcd/tap/flux` or by
 downloading the binary from [GitHub](https://github.com/fluxcd/flux2/releases).