Merge pull request #287 from strboul/readme-dev-version

Change dev version download script in the README

Author: randy3k

README.md

@@ -18,7 +18,8 @@ install.packages("languageserver")
 The development version of `languageserver` could be installed by running the following in R:
 
 ```r
-source("https://install-github.me/REditorSupport/languageserver")
+# install.packages("devtools")
+devtools::install_github("REditorSupport/languageserver")
 ```
 
 ## Language Clients