TensorBoard 2.2.0

The 2.2 minor series tracks TensorFlow 2.2.

Features

• Profile plugin now should be pip installed from tensorboard-plugin-profile.
  The new version works in Chrome 80 and Firefox, has better model insights and
  will be more actively maintained.
• Add S3_ENDPOINT variable (#3368) - thanks @thealphacod3r
• Confirm that the connection to tensorboard works or change to localhost
  (#2371) - thanks @miguelmorin
• Update --reload_multifile_inactive_secs default to 24 hours (#3243)
• New tensorboard dev update-metadata command allows for updating the name and
  description of experiments (#3277)
• Improved organization of artifacts downloaded during export from
  TensorBoard.dev (#3307)

Bug fixes

• Fix for #3282 where the tooltip would remain even after the mouse leaves the
  plot (#3347)
• Internal fix: HParams summary protos now properly include tensor values (#3386)
• Fixes to profiling tutorial (#3372 & #3381)

Breaking Changes

• Note: As of TensorBoard 2.1.1+, only Python 3 is supported. There will be no
  further releases for Python 2 as per
  https://groups.google.com/a/tensorflow.org/forum/#!topic/developers/ifEAGK3aPls