[AIRFLOW-5924] Automatically unify bucket name and key in S3Hook

[feluelle]

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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-5924
  • 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).
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Description

• Here are some details about my PR, including screenshots of any UI changes:

• change provide_bucket_name to provide bucket name also for function with keys

• refactoring

NOTE: This change is not Python 2.7 compatible. Therefore I selected Fix Version 2.0.

Tests

• My PR adds the following unit tests OR does not need testing for this extremely good reason:

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

[codecov-io]

Codecov Report

Merging #6574 into master will decrease coverage by 0.09%.
The diff coverage is 100%.

@@            Coverage Diff            @@
##           master    #6574     +/-   ##
=========================================
- Coverage    86.8%   86.71%   -0.1%     
=========================================
  Files         893      896      +3     
  Lines       42241    43283   +1042     
=========================================
+ Hits        36669    37534    +865     
- Misses       5572     5749    +177

Impacted Files	Coverage Δ
airflow/providers/amazon/aws/hooks/s3.py	96.6% <100%> (+0.74%)	⬆️
airflow/kubernetes/volume_mount.py	44.44% <0%> (-55.56%)	⬇️
airflow/kubernetes/volume.py	52.94% <0%> (-47.06%)	⬇️
airflow/kubernetes/pod_launcher.py	47.18% <0%> (-45.08%)	⬇️
...viders/cncf/kubernetes/operators/kubernetes_pod.py	69.69% <0%> (-25.26%)	⬇️
airflow/kubernetes/refresh_config.py	50.98% <0%> (-23.53%)	⬇️
airflow/__init__.py	93.33% <0%> (-6.67%)	⬇️
airflow/jobs/backfill_job.py	90.98% <0%> (-1.13%)	⬇️
...providers/microsoft/azure/hooks/azure_fileshare.py	100% <0%> (ø)	⬆️
...ow/providers/google/cloud/operators/stackdriver.py	100% <0%> (ø)
... and 10 more

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[feluelle]

Ready for Review @ashb @potiuk @mik-laj @nuclearpinguin

[feluelle]

@ashb @potiuk @mik-laj anyone? :)