Merge pull request #765 from jupyter-lsp/krassowski-pin-r-base

Add r-base version to fix Binder

Author: krassowski

binder/environment.yml

@@ -26,6 +26,8 @@ dependencies:
   - ruamel_yaml
   # for R language server and kernel
   - r
+  # workaround for https://github.com/jupyterhub/repo2docker/issues/1140
+  - r-base=4.0
   - r-irkernel
   - r-languageserver
   - rpy2