Update to 2021b (unmodified)

See commit 5053a73 (2021.2) for more
details — this is the second version fo 2021b that we are releasing due
to some controversy upstream in the direction that tzdb should take.

Author: pganssle

NEWS.md

@@ -1 +1 @@
-2021.2
+2021.2.post0

VERSION

@@ -1,6 +1,6 @@
 # IANA versions like 2020a are not valid PEP 440 identifiers; the recommended
 # way to translate the version is to use YYYY.n where `n` is a 0-based index.
-__version__ = "2021.2"
+__version__ = "2021.2.post0"
 
 # This exposes the original IANA version number.
 IANA_VERSION = "2021b"