Check storage layout consistency in PRs (#3967)

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

scripts/checks/compare-layout.js

@@ -0,0 +1,20 @@
+const fs = require('fs');
+const { getStorageUpgradeReport } = require('@openzeppelin/upgrades-core/dist/storage');
+
+const { ref, head } = require('yargs').argv;
+
+const oldLayout = JSON.parse(fs.readFileSync(ref));
+const newLayout = JSON.parse(fs.readFileSync(head));
+
+for (const name in oldLayout) {
+  if (name in newLayout) {
+    const report = getStorageUpgradeReport(oldLayout[name], newLayout[name], {});
+    if (!report.ok) {
+      console.log(`ERROR: Storage incompatibility in ${name}`);
+      console.log(report.explain());
+      process.exitCode = 1;
+    }
+  } else {
+    console.log(`WARNING: ${name} is missing from the current branch`);
+  }
+}