Do not depend on safe-buffer using caret.

package.json

@@ -4,14 +4,14 @@
   "description": "The string_decoder module from Node core",
   "main": "lib/string_decoder.js",
   "dependencies": {
-    "safe-buffer": "^5.0.1"
+    "safe-buffer": "~5.0.1"
   },
   "devDependencies": {
     "babel-polyfill": "^6.23.0",
     "tap": "~0.4.8"
   },
   "scripts": {
-    "test": "tap test/parallel/*.js"
+    "test": "tap test/parallel/*.js && node test/verify-dependencies"
   },
   "repository": {
     "type": "git",

test/verify-dependencies.js

@@ -0,0 +1,13 @@
+'use strict'
+
+var pack = require('../package.json');
+var assert = require('assert');
+
+function verifyNoCaret(deps) {
+  var keys = Object.keys(deps);
+  for (var i = 0; i < keys.length; i++) {
+    assert(deps[keys[i]][0] !== '^', keys[i] + ' must not be depended on using ^')
+  }
+}
+
+verifyNoCaret(pack.dependencies)