Merge pull request #1039 from r-lib/pkgapi

Only run {pkgapi} if available

Author: lorenzwalthert

DESCRIPTION

@@ -49,8 +49,10 @@ Suggests:
 VignetteBuilder: 
     knitr
 Encoding: UTF-8
-Roxygen: list(markdown = TRUE, roclets = c("rd", "namespace", "collate",
-    "pkgapi::api_roclet"))
+Roxygen: list(markdown = TRUE, roclets = c( "rd", "namespace", "collate",
+    if (rlang::is_installed("pkgapi")) "pkgapi::api_roclet" else {
+    warning("Please install r-lib/pkgapi to make sure the file API is kept
+    up to date"); NULL}))
 RoxygenNote: 7.2.1
 Config/testthat/edition: 3
 Config/testthat/parallel: true