Fix optional deployments regex in release CI pipeline

This commit fixes the "optional-deployments" regex for ".zip" artifacts;
"\" do not need to be escaped in YML single-quoted strings.

ci/config/release-scripts.yml

@@ -3,7 +3,7 @@ logging:
     io.spring.concourse: DEBUG
 distribute:
   optional-deployments:
-    - '.*\\.zip'
+    - '.*\.zip'
 spring:
   main:
-    banner-mode: off
+    banner-mode: off