Update changelog.main.kts, if (token == null) check (#5228)

There was a mistake in the previous PR. The warning should be printed
only if the token is omitted

# Release Notes
N/A

tools/changelog.main.kts

@@ -88,7 +88,7 @@ val argsKeyToValue = args
     .associate { it.substringBefore("=") to it.substringAfter("=") }
 
 val token = argsKeyToValue["token"]
-if (token != null) {
+if (token == null) {
     println("To increase the rate limit, specify token (https://github.com/settings/tokens), adding token=yourtoken in the end")
 }