chore: remove '*' in CODEOWNERS to allow recursive approvals (#737)

According to documentation, the pattern /path/* only allows approval on this level:
~~~
 # The `docs/*` pattern will match files like
 # `docs/getting-started.md` but not further nested files like
 # `docs/build-app/troubleshooting.md`.
 docs/*  docs@example.com

 # In this example, @doctocat owns any file in the `/docs`
 # directory in the root of your repository and any of its
 # subdirectories.
 /docs/ @doctocat
~~~
Ref: https://docs.github.com/en/github/creating-cloning-and-archiving-repositories/about-code-owners#codeowners-syntax

Signed-off-by: Marco Kilchhofer <mkilchhofer@users.noreply.github.com>

CODEOWNERS

@@ -1,7 +1,7 @@
 # https://help.github.com/en/github/creating-cloning-and-archiving-repositories/about-code-owners
 
 # All charts
-/charts/* @mkilchhofer
+/charts/ @mkilchhofer
 
 # Argo Workflows
 /charts/argo @stefansedich @paguos @vladlosev @yann-soubeyrand @oliverbaehler