ci: make lint flake8 independent step

[JoanFM]

No description provided.

[github-actions]

Latency summary

Current PR yields:

• 😶 index QPS at 1873, delta to last 3 avg.: -4%
• 😶 query QPS at 34, delta to last 3 avg.: -4%

Breakdown

Version	Index QPS	Query QPS
current	1873	34
0.8.11	1887	36
0.8.10	1970	35
0.8.9	2005	34

Backed by latency-tracking. Further commits will update this comment.

[codecov]

Codecov Report

Merging #1507 (b63aa28) into master (b91f1b7) will increase coverage by 0.27%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master    #1507      +/-   ##
==========================================
+ Coverage   84.16%   84.44%   +0.27%     
==========================================
  Files         106      106              
  Lines        6118     6183      +65     
==========================================
+ Hits         5149     5221      +72     
+ Misses        969      962       -7     

Impacted Files	Coverage Δ
jina/logging/profile.py	68.33% <0.00%> (-0.58%)	⬇️
jina/drivers/craft.py	100.00% <0.00%> (ø)
jina/types/ndarray/generic.py	100.00% <0.00%> (ø)
jina/executors/indexers/cache.py	100.00% <0.00%> (ø)
jina/executors/evaluators/text/length.py	100.00% <0.00%> (ø)
jina/executors/evaluators/rank/precision.py	100.00% <0.00%> (ø)
jina/drivers/evaluate.py	98.21% <0.00%> (+0.03%)	⬆️
jina/docker/hubio.py	69.55% <0.00%> (+0.08%)	⬆️
jina/enums.py	96.52% <0.00%> (+0.09%)	⬆️
jina/jaml.py	91.66% <0.00%> (+0.11%)	⬆️
... and 19 more

---

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[JoanFM]

@hanxiao if accepted, how can I have the flake8 analysis as a required step?

[hanxiao]

why separate it from the main ci jobs?

[JoanFM]

why separate it from the main ci jobs?

no big deal, to have only one and not one per version