Use a 256 bit hash for DeepHash() (making collisions even less likely).

pkg/varnish/vcl/spec.go

@@ -105,7 +105,7 @@ type Spec struct {
 // for equivalence by content, and are considered unchanged when only
 // their metadata change.
 func (spec Spec) DeepHash() []byte {
-	hash := sha512.New512_224()
+	hash := sha512.New512_256()
 
 	hash.Write([]byte(spec.Version))
 	hash.Write([]byte(spec.Main))