fix appveyor with kwb.pkgbuild::use_appveyor()

appveyor.yml

@@ -1,3 +1,18 @@
+##############################################################################
+### Autogenerated with R package kwb.pkgbuild v0.0.0.9000
+### (installed from 'Github (kwb-r/kwb.pkgbuild@5ce7e12)' source code on 2019-03-14)
+### by calling the function kwb.pkgbuild::use_appveyor()
+### (file created at: 2019-03-14 21:28:44)
+##############################################################################
+
+
+
+### Configuration copied from: 
+### https://raw.githubusercontent.com/tidyverse/readxl/5649e2643d25bb5b6353797fc48bbcbb0eb72f6d/appveyor.yml"
+### But in addition also use two environment variables: 
+### - USE_RTools = true(for details see: https://github.com/KWB-R/kwb.pkgbuild/issues/37) 
+### - R_REMOTES_STANDALONE = true (for details see: https://github.com/r-lib/remotes#standalone-mode, https://github.com/krlmlr/r-appveyor/issues/135) 
+
 # DO NOT CHANGE the "init" and "install" sections below
 
 # Download script file from GitHub
@@ -16,7 +31,11 @@ cache:
 # Adapt as necessary starting from here
 
 environment:
+### Add RTools (for details see: https://github.com/KWB-R/kwb.pkgbuild/issues/37)
   USE_RTOOLS: true
+### Add R_REMOTES_STANDALONE(for details see: https://github.com/krlmlr/r-appveyor/issues/135 
+### or https://github.com/r-lib/remotes#standalone-mode)  
+  R_REMOTES_STANDALONE: true
 
 build_script:
   - travis-tool.sh install_deps