Clean up GHA workflow

Author: csoneson

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

@@ -91,11 +91,6 @@ jobs:
           remotes::install_cran('rcmdcheck', Ncpu = 2L)
         shell: Rscript {0}
 
-      - name: Install ggalt manually (currently missing from CRAN)
-        run: |
-          remotes::install_version("ggalt", version = "0.4.0")
-        shell: Rscript {0}
-    
       - name: Session info
         run: |
           options(width = 100)