drop_read : wrapper function for readxl, readRDS, load and readcsv

Please start your issue with a brief description of the problem.

I would like to read different formatt files from dropbox. I saw drop_read.csv which is great. then I create one taking account excel file and R native format such as rdata, rds etc.

I will suggest you a pull request for that

Start by reviewing the existing drop_read.csv entry point and the issue's requested support for Excel and R-native formats such as RData and RDS. Confirm which formats the wrapper should cover and define completion around reading those files from Dropbox consistently; no test file or additional entry point is mentioned.

Written by the indexing model from the issue text.