dont check on devel ubuntu

Author: daattali

.github/workflows/R-CMD-check.yaml

@@ -21,7 +21,6 @@ jobs:
           - {os: windows-latest, r: 'release'}
           - {os: macOS-latest, r: 'release'}
           - {os: ubuntu-20.04, r: 'release', rspm: "https://packagemanager.rstudio.com/cran/__linux__/focal/latest"}
-          - {os: ubuntu-20.04, r: 'devel', rspm: "https://packagemanager.rstudio.com/cran/__linux__/focal/latest"}
 
     env:
       R_REMOTES_NO_ERRORS_FROM_WARNINGS: true