Add dev/appveyor-install-dependencies.ps1 too

Author: HyukjinKwon

appveyor.yml

@@ -27,6 +27,7 @@ branches:
 only_commits:
   files:
     - appveyor.yml
+    - dev/appveyor-install-dependencies.ps1
     - R/
     - sql/core/src/main/scala/org/apache/spark/sql/api/r/
     - core/src/main/scala/org/apache/spark/api/r/