Fix badges URL

Author: Swechhya

README.md

@@ -1,6 +1,6 @@
 # excelR
-[![version](http://www.r-pkg.org/badges/version/excelR)](https://CRAN.R-project.org/package=excelR)
-[![CRAN_Download_Badge](http://cranlogs.r-pkg.org/badges/grand-total/excelR)](http://cran.r-project.org/package=excelR)
+[![version](https://www.r-pkg.org/badges/version/excelR)](https://CRAN.R-project.org/package=excelR)
+[![CRAN_Download_Badge](https://cranlogs.r-pkg.org/badges/grand-total/excelR)](https://cran.r-project.org/package=excelR)
 [![Travis-CI Build Status](https://travis-ci.org/Swechhya/excelR.svg?branch=master)](https://travis-ci.org/Swechhya/excelR)
 [![AppVeyor Build Status](https://ci.appveyor.com/api/projects/status/github/Swechhya/excelR?branch=master&svg=true)](https://ci.appveyor.com/project/Swechhya/excelR)
 [![codecov](https://codecov.io/gh/Swechhya/excelR/branch/master/graph/badge.svg)](https://codecov.io/gh/Swechhya/excelR)