fix(ci): add exclusion in .lint file

Author: Duologic

.lint

@@ -5,3 +5,5 @@ exclusions:
  target-instance-rule:
  panel-title-description-rule:
  panel-units-rule:
+ panel-datasource-rule:
+  reason: The new Grafonnet promotes the use of datasources at the query level. This should probably end up in the linter as a valid option.