Use SVG badge (#24)

Author: AlekSi

README.md

@@ -3,7 +3,7 @@ gofuzz
 
 gofuzz is a library for populating go objects with random values.
 
-[![GoDoc](https://godoc.org/github.com/google/gofuzz?status.png)](https://godoc.org/github.com/google/gofuzz)
+[![GoDoc](https://godoc.org/github.com/google/gofuzz?status.svg)](https://godoc.org/github.com/google/gofuzz)
 [![Travis](https://travis-ci.org/google/gofuzz.svg?branch=master)](https://travis-ci.org/google/gofuzz)
 
 This is useful for testing: