chore: fix enterprise chart version typo

deploy/charts/emqx-enterprise/Chart.yaml

@@ -18,4 +18,4 @@ version: 5.3.1-alpha.1
 
 # This is the version number of the application being deployed. This version number should be
 # incremented each time you make changes to the application.
-appVersion: 5.3.-alpha.1
+appVersion: 5.3.1-alpha.1