Automate a PR to update func-e

[codefromthecrypt]

On release of next version, we should be able to do an update to func-e. Notes:

• Not all versions will change the last known version. For example, if 1.20.0 is latest and a release here adds a patch to 1.19, there's noop and should be no pull request.
• There is some variable substitution needed ex. https://github.com/tetratelabs/func-e/pull/399
• Testing such a change would be best done against someone's fork, not func-e itself, and it may be hard to test anyway.