[pep-569] Clarify 3.8.0 release date assuming a single RC

Author: ambv

pep-0569.rst

@@ -65,7 +65,7 @@ Expected:
 
 - 3.8.0 candidate 1: Monday, 2019-09-30
 - 3.8.0 candidate 2: Monday, 2019-10-07 (if necessary)
-- 3.8.0 final: Monday, 2019-10-21
+- 3.8.0 final: Monday, 2019-10-14 (assuming a single release candidate)
 
 Subsequent bugfix releases at a monthly cadence.