Bump pytz from 2020.1 to 2021.1

Bumps pytz from 2020.1 to 2021.1.

Commits

• b3b0aef Bump version numbers to 2021.1/2021a
• f8bad81 IANA 2021a
• 560c127 Squashed 'tz/' changes from efc5c06192..4f0b29ebf7
• 76ed158 2020.5 / 2020e release
• aaef58a Squashed 'tz/' changes from 9c175ec6c..a816a5c4d
• b83f879 IANA 2020e
• 6cf10f2 Drop Python 3.0 support from distribution metadata
• 7d0205f List Py3.9 support in distribution metadata
• 513450f Drop unwanted and unecessary shebang line
• d6a6878 Generate fat datafiles
• Additional commits viewable in compare view