skip example 005 for R < 4.1.0, and use git diff --quiet to test differences (since [ -z ] doesn't work on Windows)

Author: yihui

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

@@ -80,7 +80,7 @@ jobs:
         working-directory: examples
         run: |
           Rscript _run.R
-          [ -z "$(git diff)" ] || (git diff && echo "Examples output changed" 1>&2 && exit 1)
+          git diff --quiet || (echo "Examples output changed" 1>&2 && exit 1)
 
       - name: Test coverage
         if: success() && env.USE_R_CODECOV == 'true'

examples/_run.R

@@ -7,6 +7,8 @@ for (f in litedown:::find_input('.')) {
     m = file.mtime(c(f, f2 <- xfun::with_ext(f, '.md')))
     if (!is.na(m[2]) && m[1] < m[2]) next
   }
+  # example 005 uses |>, which is available only in R >= 4.1.0
+  if (grepl('/005-', f) && getRversion() < '4.1.0') next
   xfun::Rscript_call(function(.) {
     options(width = 80, litedown.jsd_resolve = FALSE)
     if (xfun::file_ext(.) == 'md') litedown::mark(.) else litedown::fuse(., '.md')