Increased Minor Version

package.json

 {
   "name": "zeppelin-solidity",
-  "version": "1.5.0",
+  "version": "1.5.1",
   "description": "Secure Smart Contract library for Solidity",
   "scripts": {
     "test": "scripts/test.sh",
@@ -52,4 +52,4 @@
   "dependencies": {
     "dotenv": "^4.0.0"
   }
-}
+}
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