Update cron date (#6132)

Author: MichaelChirico

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

@@ -1,6 +1,6 @@
 on:
   schedule:
-   - cron: '18 13 10 * *' # 8th of month at 13:18 UTC
+   - cron: '18 13 11 * *' # 11th of month at 13:18 UTC
 
 # A more complete suite of checks to run monthly; each PR/merge need not pass all these, but they should pass before CRAN release
 name: R-CMD-check-occasional