Upgrade fasthttp to v1.4.0

Author: Sergio Andres Virviescas Santana

go.mod

@@ -3,5 +3,5 @@ module github.com/fasthttp/router
 require (
 	github.com/savsgio/gotils v0.0.0-20190409142739-e36d23089e10
 	github.com/valyala/bytebufferpool v1.0.0
-	github.com/valyala/fasthttp v1.3.0
+	github.com/valyala/fasthttp v1.4.0
 )

go.sum

@@ -6,7 +6,7 @@ github.com/savsgio/gotils v0.0.0-20190409142739-e36d23089e10 h1:Rk4AHSMs6BX9Vb84
 github.com/savsgio/gotils v0.0.0-20190409142739-e36d23089e10/go.mod h1:w803/Fg1m0hrp1ZT9KNfQe4E4+WOMMFLcgzPvOcye10=
 github.com/valyala/bytebufferpool v1.0.0 h1:GqA5TC/0021Y/b9FG4Oi9Mr3q7XYx6KllzawFIhcdPw=
 github.com/valyala/bytebufferpool v1.0.0/go.mod h1:6bBcMArwyJ5K/AmCkWv1jt77kVWyCJ6HpOuEn7z0Csc=
-github.com/valyala/fasthttp v1.3.0 h1:++0WUtakkqBuHHY5JRFFl6O44I03XLBqxNnrBX0yH7Y=
-github.com/valyala/fasthttp v1.3.0/go.mod h1:4vX61m6KN+xDduDNwXrhIAVZaZaZiQ1luJk8LWSxF3s=
+github.com/valyala/fasthttp v1.4.0 h1:PuaTGZIw3mjYhhhbVbCQp8aciRZN9YdoB7MGX9Ko76A=
+github.com/valyala/fasthttp v1.4.0/go.mod h1:4vX61m6KN+xDduDNwXrhIAVZaZaZiQ1luJk8LWSxF3s=
 github.com/valyala/tcplisten v0.0.0-20161114210144-ceec8f93295a/go.mod h1:v3UYOV9WzVtRmSR+PDvWpU/qWl4Wa5LApYYX4ZtKbio=
 golang.org/x/net v0.0.0-20180911220305-26e67e76b6c3/go.mod h1:mL1N/T3taQHkDXs73rZJwtUhF3w3ftmwwsq0BUmARs4=