Require sodium_compat v1.5.5

Author: lookyman

composer.json

@@ -8,7 +8,8 @@
     "roave/security-advisories": "dev-master",
     "php-http/httplug": "^1.1",
     "paragonie/sapient": "^1.0",
-    "http-interop/http-factory": "^0.3.0"
+    "http-interop/http-factory": "^0.3.0",
+    "paragonie/sodium_compat": "^1.5.5"
   },
   "require-dev": {
     "jakub-onderka/php-parallel-lint": "^0.9.2",