fix: Dont save hackage-creds

Author: Nick Tchayka

stack.yaml

@@ -18,6 +18,7 @@
 # resolver: ./custom-snapshot.yaml
 # resolver: https://example.com/snapshots/2018-01-01.yaml
 resolver: lts-19.18
+save-hackage-creds: false
 
 # User packages to be built.
 # Various formats can be used as shown in the example below.