materialize: move env variable(s) into env for structuredAttrs

pkgs/by-name/ma/materialize/package.nix

@@ -92,7 +92,6 @@ in
 rustPlatform.buildRustPackage rec {
   pname = "materialize";
   version = "0.87.2";
-  MZ_DEV_BUILD_SHA = "000000000000000000000000000000000000000000000000000";
 
   src = fetchFromGitHub {
     owner = "MaterializeInc";
@@ -112,6 +111,7 @@ rustPlatform.buildRustPackage rec {
   '';
 
   env = {
+    MZ_DEV_BUILD_SHA = "000000000000000000000000000000000000000000000000000";
     # needed for internal protobuf c wrapper library
     PROTOC = lib.getExe protobuf;
     PROTOC_INCLUDE = "${protobuf}/include";