Bump appveyor version number.

bearoso · bearoso · commit e2e3f8604e73 · 2018-11-09T18:50:30.000-06:00
diff --git a/appveyor.yml b/appveyor.yml
@@ -1,4 +1,4 @@
-version: 1.56.2-{build}
+version: 1.57-{build}
 
 image: Visual Studio 2017
 
