playground: Finish migrating pgbundle to release.go.playground.

Change-Id: I6f658ae48e778264e67deebef9a1ba6933e4c2f9
diff --git a/pgbundle/Makefile b/pgbundle/Makefile
index 4ba5419..f52e1d6 100644
--- a/pgbundle/Makefile
+++ b/pgbundle/Makefile
@@ -4,7 +4,7 @@
 node_modules: package.json
 	@npm prune
 	npm install
-	@touch node_modules
+	@touch $@
 
 .PHONY: clean
 clean: