fix(package): update semver to version 5.4.1

Closes #2015

package.json

@@ -25,7 +25,7 @@
     "js-yaml"               : "~3.9.0",
     "nopt"                  : "~4.0.1",
     "npid"                  : "~0.4.0",
-    "semver"                : "~5.3.0",
+    "semver"                : "~5.4.1",
     "sprintf-js"            : "~1.1.0",
     "haraka-tld"            : "*",
     "haraka-constants"      : ">=1.0.4",