fix(tests) fix tests failing on Lua 5.4

tests/lua/mod52.lua

@@ -10,9 +10,17 @@ local _ENV,M = require 'pl.import_into' (rawget(_G,'STRICT'))
 function answer ()
     -- of course, you don't have the usual global environment available
     -- so define it as a local up above, or use utils.import(_G).
+
+    local versioned_errors = {
+        ["1"] = "attempt to call global 'print'",
+        ["2"] = "attempt to call global 'print'",
+        ["3"] = "attempt to call a nil value",
+        ["4"] = "attempt to call a nil value",
+    }
+    local expected = versioned_errors[LUA_VERSION:match("Lua 5.(%d)")]
     test.assertraise(function()
         print 'hello'
-    end,(LUA_VERSION~="Lua 5.3") and "attempt to call global 'print'" or "attempt to call a nil value")
+    end, expected)
 
     -- but all the Penlight modules are available
     return pretty.write(utils.split '10 20  30', '')