ci: fix versions.hcl parsing by removing extraneous comma (#21752)

Commas are not expected after HCL blocks. This is causing parsing in BPA
to fail and may interfere w/ other release-related workflows.

.release/versions.hcl

@@ -8,7 +8,7 @@ schema = 1
 active_versions {
   version "1.20" {
     ce_active = true
-  },
+  }
   version "1.19" {
     ce_active = true
   }