Add exemption for artifact hub (#4824)

Co-authored-by: Riccardo Magliocchetti <riccardo.magliocchetti@gmail.com>

Author: thompson-tomo

.clomonitor.yml

@@ -0,0 +1,4 @@
+# see https://github.com/cncf/clomonitor/blob/main/docs/checks.md#exemptions
+exemptions:
+  - check: artifacthub_badge
+    reason: "Artifact Hub doesn't support python packages"