don't force suggest as data.tree is not available for R 3.4

Author: lorenzwalthert

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

@@ -89,6 +89,7 @@ jobs:
       - name: Check
         env:
           _R_CHECK_CRAN_INCOMING_: false
+          _R_CHECK_FORCE_SUGGESTS_: false
         run: |
           options(crayon.enabled = TRUE)
           rcmdcheck::rcmdcheck(args = c("--no-manual", "--as-cran"), error_on = "warning", check_dir = "check")