bump vm-builder version to v0.15.4 (neondatabase#4980)

Patches a bug in vm-builder where it did not include enough parameters
in the query string. These parameters are `host=localhost port=5432`.
These parameters were not necessary for the monitor because the `pq` go
postgres driver included them by default.

.github/workflows/build_and_test.yml

@@ -814,7 +814,7 @@ jobs:
       run:
         shell: sh -eu {0}
     env:
-      VM_BUILDER_VERSION: v0.15.0-alpha1
+      VM_BUILDER_VERSION: v0.15.4
 
     steps:
       - name: Checkout