chore: update cli to 1.5.20 for GKE UI extensions

This is for: #3146

Author: g-awmalik

cli/Makefile

@@ -1,7 +1,7 @@
 SHELL := /bin/bash
 
 # Changing this value will trigger a new release
-VERSION=v1.5.19
+VERSION=v1.5.20
 BINARY=bin/cft
 GITHUB_REPO=github.com/GoogleCloudPlatform/cloud-foundation-toolkit
 PLATFORMS := linux windows darwin