[AIRFLOW-4753] Utils log json formatter

[potiuk]

Make sure you have checked all steps below.

Jira

• My PR addresses the following Airflow Jira issues and references them in the PR title. For example, "[AIRFLOW-XXX] My Airflow PR"
  • https://issues.apache.org/jira/browse/AIRFLOW-4753
  • In case you are fixing a typo in the documentation you can prepend your commit with [AIRFLOW-XXX], code changes always need a Jira issue.
  • In case you are proposing a fundamental code change, you need to create an Airflow Improvement Proposal (AIP).
  • In case you are adding a dependency, check if the license complies with the ASF 3rd Party License Policy.

Description

• Here are some details about my PR, including screenshots of any UI changes:
  Fixes pylint for the formatter.

Tests

• My PR adds the following unit tests OR does not need testing for this extremely good reason:
  No tests.

Commits

• My commits all reference Jira issues in their subject lines, and I have squashed multiple commits if they address the same issue. In addition, my commits follow the guidelines from "How to write a good git commit message":
  1. Subject is separated from body by a blank line
  2. Subject is limited to 50 characters (not including Jira issue reference)
  3. Subject does not end with a period
  4. Subject uses the imperative mood ("add", not "adding")
  5. Body wraps at 72 characters
  6. Body explains "what" and "why", not "how"

Documentation

• In case of new functionality, my PR adds documentation that describes how to use it.
  • All the public functions and the classes in the PR contain docstrings that explain what it does
  • If you implement backwards incompatible changes, please leave a note in the Updating.md so we can assign it to a appropriate release

Code Quality

• Passes flake8

[codecov-io]

Codecov Report

Merging #5393 into master will increase coverage by <.01%.
The diff coverage is 100%.

@@            Coverage Diff             @@
##           master    #5393      +/-   ##
==========================================
+ Coverage   79.02%   79.02%   +<.01%     
==========================================
  Files         481      481              
  Lines       30203    30203              
==========================================
+ Hits        23868    23869       +1     
+ Misses       6335     6334       -1

Impacted Files	Coverage Δ
airflow/utils/log/json_formatter.py	100% <100%> (ø)	⬆️
airflow/models/taskinstance.py	92.61% <0%> (+0.17%)	⬆️

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 3e99121...60b32c6. Read the comment docs.

[BasPH]

Tiny nit: to keep ! -name 'webserver_config.py' consistent with the other code, would use -not:

-not -name 'webserver_config.py'

[BasPH]

This PR contains 2 commits, one should be for your other PR

[potiuk]

Yep. It was based on the previous change. I rebased it on master now.

[potiuk]

Should be ok now @BasPH