Don’t strip postfix to enable padding it

[flying-sheep]

Currently, doing pbar.set_postfix(header=f'{header:<30}') does nothing.
This restores the ability to have things not jump all over the place.

• I have marked all applicable categories:
  • visual output fix
• If applicable, I have mentioned the relevant/related issue(s)

Less important but also useful:

• I have visited the source website, and in particular
  read the known issues
• I have searched through the issue tracker for duplicates
• I have mentioned version numbers, operating system and
  environment

[casperdcl]

@flying-sheep could you fix the unit tests?

[flying-sheep]

Not much I can do about

ERROR: No matching distribution found for tensorflow

I also only have Linux machines, and on Linux, there is no breakage

[codecov]

Codecov Report

Merging #884 (e06a544) into master (9590fa1) will decrease coverage by 3.17%.
The diff coverage is 100.00%.

❗ Current head e06a544 differs from pull request most recent head 0a48f66. Consider uploading reports for the commit 0a48f66 to get more accurate results

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #884      +/-   ##
==========================================
- Coverage   87.73%   84.56%   -3.17%     
==========================================
  Files          26       17       -9     
  Lines        1712     1108     -604     
  Branches      296      196     -100     
==========================================
- Hits         1502      937     -565     
- Misses        154      158       +4     
+ Partials       56       13      -43