[DOC] update changelog and git blame ignore

[Remi-Gau]

Closes #3752
Relates to #3653

Changes proposed in this pull request:

• update git blame ignore
• update changelog with changes for pep8 and isort compliance

[github-actions]

👋 @Remi-Gau Thanks for creating a PR!

Until this PR is ready for review, you can include the [WIP] tag in its title, or leave it as a github draft.

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[codecov]

Codecov Report

Merging #3755 (f3c7add) into main (f16dcb4) will increase coverage by 0.06%.
The diff coverage is 100.00%.

❗ Current head f3c7add differs from pull request most recent head 568125a. Consider uploading reports for the commit 568125a to get more accurate results

@@            Coverage Diff             @@
##             main    #3755      +/-   ##
==========================================
+ Coverage   91.54%   91.60%   +0.06%     
==========================================
  Files         139      139              
  Lines       16591    16591              
  Branches     3244     3244              
==========================================
+ Hits        15188    15198      +10     
+ Misses       1402     1390      -12     
- Partials        1        3       +2     

Impacted Files	Coverage Δ
nilearn/plotting/matrix_plotting.py	96.59% <100.00%> (ø)

... and 5 files with indirect coverage changes

📣 We’re building smart automated test selection to slash your CI/CD build times. Learn more

[Remi-Gau]

Related to #3701 (comment)

 git blame --ignore-revs-file .git-blame-ignore-revs nilearn/image/resampling.py 

Still shows content from 3651 event though it is supposed to be ignored:

# run isort and flake8 on the whole nilearn code base in CI (#3651)
44933309ecd09add795ce1c3ea5edaab4294da87

More annoyingly it is also still the case for:

 git blame --ignore-rev 44933309  nilearn/image/resampling.py

[Remi-Gau]

Behavior is the same on the github interface that supposedly picks up on git blame ignore:

https://github.com/Remi-Gau/nilearn/blame/ignore_blame/nilearn/image/resampling.py

[Remi-Gau]

things I have tried:

• only having the commit shasum in the file with no comment (help identify invalid commit number but does not fix the issue)

[Remi-Gau]

I still cannot make the git blame ignore work properly to ignore the PRs listed in it but at least the PRs for flake8 and isort compliance are listed

[ymzayek]

@Remi-Gau it LGTM! I think then we can leave #3653 open with a comment that we still need to get it to work. But I'm ok for merging this PR

[Remi-Gau]

yup that was my idea.

Merging this then.