update changelog entry with link to PR

Author: netomi

cli/CHANGELOG.md

@@ -6,7 +6,7 @@ This change log covers only the command line interface (CLI) of Open VSX.
 
 #### Fixes
 
-- Support custom registry url including a subpath
+- Support custom registry url including a subpath ([#1542](https://github.com/eclipse/openvsx/pull/1542))
 
 #### Changes