drop! postgresql_9: sha256 -> hash

But postgresql 9 is unsupported, just kept alive for no reason.

Author: jsoo1

pkgs/servers/sql/postgresql/default.nix

@@ -209,7 +209,7 @@ in self: {
   postgresql_9_6 = self.callPackage generic {
     version = "9.6.24";
     psqlSchema = "9.6";
-    sha256 = "sha256-rrehlr4+vtGnR271ZfOXIhh8EI3UfadIm+nE/K6YKs4=";
+    hash = "sha256-rrehlr4+vtGnR271ZfOXIhh8EI3UfadIm+nE/K6YKs4=";
     this = self.postgresql_9_6;
     thisAttr = "postgresql_9_6";
     inherit self;