one job to avoid mixing all 4 logs

Author: phated

compiler/package.json

@@ -19,7 +19,7 @@
     "prebuild": "npm run clean --workspace=@grain/cli",
     "build": "esy",
     "postbuild": "esy copy:exe",
-    "build:js": "esy b dune build @js --no-buffer",
+    "build:js": "esy b dune build @js --no-buffer -j 1",
     "postbuild:js": "esy copy:js",
     "pretest": "npm run build",
     "test": "esy test",