Stop checking on 4.1 on Windows

This is motivated by R CMD check failures in GHA, because ragg fails to install with the older toolchain. Doesn't feel like a devtools problem.

Author: jennybc

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

@@ -26,8 +26,14 @@ jobs:
           - {os: macos-latest,   r: 'release'}
 
           - {os: windows-latest, r: 'release'}
+          # specifying oldrel-3 instead of oldrel-4, because ragg is a problem
+          # and that's what ragg itself is doing (???)
+          # seems like we lose coverage of rtools40's compiler, but that also
+          # doesn't seem like a devtools problem
+          # https://github.com/r-lib/ragg/pull/195/commits/0ce19424eab2dad15b38b41992804e3226d86e22
+          - {os: windows-latest, r: 'oldrel-3'}
           # use 4.0 or 4.1 to check with rtools40's older compiler
-          - {os: windows-latest, r: 'oldrel-4'}
+          #- {os: windows-latest, r: 'oldrel-4'}
 
           - {os: ubuntu-latest,  r: 'devel', http-user-agent: 'release'}
           - {os: ubuntu-latest,  r: 'release'}