Fix windows tests, forcing lf instead of crlf on windows

Signed-off-by: Silvin Lubecki <silvin.lubecki@docker.com>

.gitattributes

@@ -0,0 +1,7 @@
+* text=auto
+* text eol=lf
+*.png binary
+*.exe binary
+*.ico binary
+*.jar binary
+vendor/** -text