add snapshot varient for R version < 4.3

Author: t-kalinowski

tests/testthat/_snaps/R-lt-4-3/method-dispatch.md

@@ -0,0 +1,8 @@
+# method dispatch works for class_missing
+
+    Code
+      foo_wrapper()
+    Condition
+      Error in `S7::S7_dispatch()`:
+      ! argument "xx" is missing, with no default
+

tests/testthat/test-method-dispatch.R

@@ -220,6 +220,10 @@ test_that("method dispatch works for class_missing", {
 
   # dispatch on class_missing only works directly in the generic call
   foo_wrapper <- function(xx) foo(xx)
-  expect_snapshot(error = TRUE, foo_wrapper())
+  expect_snapshot(
+    error = TRUE,
+    variant = if (getRversion() < "4.3") "R-lt-4-3",
+    foo_wrapper()
+  )
 
 })