use SVG in Travis badge

this improves the sharpness of the resulting image to match the quality of the other badges.

diff --git a/Readme.md b/Readme.md
index 96ba0b4..6b33168 100644 (file)
--- a/Readme.md
+++ b/Readme.md
@@ -1,7 +1,7 @@
 Open Asset Import Library (assimp)\r
 ==================================\r
 \r
-[![Linux Build Status](https://travis-ci.org/assimp/assimp.png)](https://travis-ci.org/assimp/assimp)\r
+[![Linux Build Status](https://travis-ci.org/assimp/assimp.svg)](https://travis-ci.org/assimp/assimp)\r
 [![Windows Build Status](https://ci.appveyor.com/api/projects/status/tmo433wax6u6cjp4?svg=true)](https://ci.appveyor.com/project/kimkulling/assimp)\r
 <a href="https://scan.coverity.com/projects/5607">\r
   <img alt="Coverity Scan Build Status"\r