Merge pull request #1913 from request/greenkeeper-http-signature-1.1.0

Update http-signature to version 1.1.0 🚀

package.json

@@ -33,7 +33,7 @@
     "qs": "~5.2.0",
     "tunnel-agent": "~0.4.1",
     "tough-cookie": "~2.2.0",
-    "http-signature": "~1.0.2",
+    "http-signature": "~1.1.0",
     "oauth-sign": "~0.8.0",
     "hawk": "~3.1.0",
     "aws-sign2": "~0.6.0",