Re-enable coverage analysis (#2291)

Co-authored-by: Francisco Giordano <frangio.1@gmail.com>

scripts/coverage.js

@@ -0,0 +1,21 @@
+#!/usr/bin/env node
+
+const { execSync } = require('child_process');
+const { runCoverage } = require('@openzeppelin/test-environment');
+
+async function main () {
+  await runCoverage(
+    ['mocks'],
+    'npm run compile',
+    './node_modules/.bin/mocha --exit --timeout 10000 --recursive'.split(' '),
+  );
+
+  if (process.env.CI) {
+    execSync('curl -s https://codecov.io/bash | bash -s -- -C "$CIRCLE_SHA1"', { stdio: 'inherit' });
+  }
+}
+
+main().catch(e => {
+  console.error(e);
+  process.exit(1);
+});