Update PEP 494 with a detailed Python 3.6 release schedule proposal

pep-0494.txt

@@ -19,7 +19,7 @@ items.
 
 .. Small features may be added up to the first beta
    release.  Bugs may be fixed until the final release,
-   which is planned for September 2015.
+   which is planned for December 2016.
 
 
 Release Manager and Crew
@@ -31,17 +31,37 @@ Release Manager and Crew
 - Documentation: Georg Brandl
 
 
+3.6 Lifespan
+============
+
+3.6 will receive bugfix updates approximately every 3-6 months for
+approximately 18 months.  After the release of 3.7.0 final, a final
+3.6 bugfix update will be released.  After that, it is expected that
+security updates (source only) will be released until 5 years after
+the release of 3.6 final, so until approximately December 2021.
+
+
 Release Schedule
 ================
 
-The releases:
+3.6.0 schedule
+--------------
 
-- 3.6.0 alpha 1: TBD
-- 3.6.0 beta 1: TBD
-- 3.6.0 candidate 1: TBD
-- 3.6.0 final: TBD (late 2016?)
+- 3.6 development begins: 2015-05-24
+- 3.6.0 alpha 1: 2016-05-15
+- 3.6.0 alpha 2: 2016-06-12
+- 3.6.0 alpha 3: 2016-07-10
+- 3.6.0 alpha 4: 2016-08-07
+- 3.6.0 beta 1: 2016-09-07
 
-(Beta 1 is also "feature freeze"--no new features beyond this point.)
+(No new features beyond this point.)
+
+- 3.6.0 beta 2: 2016-10-02
+- 3.6.0 beta 3: 2016-10-30
+- 3.6.0 beta 4: 2016-11-20
+- 3.6.0 candidate 1: 2016-12-04
+- 3.6.0 candidate 2 (if needed): 2016-12-11
+- 3.6.0 final: 2016-12-16
 
 
 Features for 3.6