separate prepare and prepack scripts to fix CI

package.json

@@ -20,7 +20,8 @@
     "lint:js": "eslint --ignore-path .gitignore .",
     "lint:js:fix": "eslint --ignore-path .gitignore . --fix",
     "lint:sol": "solhint --max-warnings 0 \"contracts/**/*.sol\"",
-    "prepare": "node scripts/prepare.js",
+    "prepare": "npm run compile",
+    "prepack": "node scripts/remove-ignored-artifacts.js",
     "release": "scripts/release/release.sh",
     "version": "scripts/release/version.sh",
     "test": "mocha --exit --recursive"

scripts/remove-ignored-artifacts.js

@@ -4,15 +4,12 @@
 
 const fs = require('fs');
 const path = require('path');
-const cp = require('child_process');
 const match = require('micromatch');
 
 function readJSON (path) {
   return JSON.parse(fs.readFileSync(path));
 }
 
-cp.spawnSync('npm', ['run', 'compile'], { stdio: 'inherit' });
-
 const pkgFiles = readJSON('package.json').files;
 
 // Get only negated patterns.