Prepare for next version after 1.5.0 (#289)

Author: jsoriano

versions/1/changelog.yml

@@ -2,6 +2,11 @@
 ## This file documents changes in the package specification. It is NOT a package specification file.
 ## Newer entries go at the bottom.
 ##
+- version: 1.5.1-next
+  changes:
+  - description: Prepare for next version
+    type: enhancement
+    link: https://github.com/elastic/package-spec/pull/289
 - version: 1.5.0
   changes:
   - description: Add kibana/csp-rule-template asset