Update appveyor.yml

Simplify dart-sdk install?
diff --git a/appveyor.yml b/appveyor.yml
index 7b71705..5848228 100644
--- a/appveyor.yml
+++ b/appveyor.yml
@@ -4,8 +4,6 @@
 
 install:
   - choco install -y dart-sdk -version 1.10.0
-  - set PATH=%PATH%;C:\tools\dart-sdk\bin
-  - set PATH=%PATH%;%APPDATA%\Pub\Cache\bin
   - pub get
 
 build: off