replace travis/appveyor badges with gh-actions badge

Author: sckott

README.Rmd

@@ -11,8 +11,7 @@ knitr::opts_chunk$set(
 ```
 
 [![cran checks](https://cranchecks.info/badges/worst/gistr)](https://cranchecks.info/pkgs/gistr)
-[![Build Status](https://api.travis-ci.org/ropensci/gistr.png)](https://travis-ci.org/ropensci/gistr)
-[![Build status](https://ci.appveyor.com/api/projects/status/4jmuxbbv8qg4139t/branch/master?svg=true)](https://ci.appveyor.com/project/sckott/gistr/branch/master)
+[![R-check](https://github.com/ropensci/gistr/workflows/R-check/badge.svg)](https://github.com/ropensci/gistr/actions/)
 [![codecov.io](https://codecov.io/github/ropensci/gistr/coverage.svg?branch=master)](https://codecov.io/github/ropensci/gistr?branch=master)
 [![rstudio mirror downloads](https://cranlogs.r-pkg.org/badges/gistr)](https://github.com/metacran/cranlogs.app)
 [![cran version](https://www.r-pkg.org/badges/version/gistr)](https://cran.r-project.org/package=gistr)

README.md

@@ -4,8 +4,7 @@ gistr
 
 
 [![cran checks](https://cranchecks.info/badges/worst/gistr)](https://cranchecks.info/pkgs/gistr)
-[![Build Status](https://api.travis-ci.org/ropensci/gistr.png)](https://travis-ci.org/ropensci/gistr)
-[![Build status](https://ci.appveyor.com/api/projects/status/4jmuxbbv8qg4139t/branch/master?svg=true)](https://ci.appveyor.com/project/sckott/gistr/branch/master)
+[![R-check](https://github.com/ropensci/gistr/workflows/R-check/badge.svg)](https://github.com/ropensci/gistr/actions/)
 [![codecov.io](https://codecov.io/github/ropensci/gistr/coverage.svg?branch=master)](https://codecov.io/github/ropensci/gistr?branch=master)
 [![rstudio mirror downloads](https://cranlogs.r-pkg.org/badges/gistr)](https://github.com/metacran/cranlogs.app)
 [![cran version](https://www.r-pkg.org/badges/version/gistr)](https://cran.r-project.org/package=gistr)