[Enhance] Upgrade isort pre-commit hooks.

[mzr1996]

Motivation

Our isort hook is outdated, use new version isort hook.

Modification

As the title.

Checklist

Before PR:

• Pre-commit or other linting tools are used to fix the potential lint issues.
• Bug fixes are fully covered by unit tests, the case that causes the bug should be added in the unit tests.
• The modification is covered by complete unit tests. If not, please add more unit test to ensure the correctness.
• The documentation has been modified accordingly, like docstring or example tutorials.

After PR:

• If the modification has potential influence on downstream or other related projects, this PR should be tested with those projects, like MMDet or MMSeg.
• CLA has been signed and all committers have signed the CLA in this PR.

[codecov]

Codecov Report

Merging #687 (c61c078) into dev (bca695b) will not change coverage.
The diff coverage is 50.00%.

@@           Coverage Diff           @@
##              dev     #687   +/-   ##
=======================================
  Coverage   85.01%   85.01%           
=======================================
  Files         120      120           
  Lines        7362     7362           
  Branches     1271     1271           
=======================================
  Hits         6259     6259           
  Misses        915      915           
  Partials      188      188           

Flag	Coverage Δ
unittests	85.01% <50.00%> (ø)

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
mmcls/apis/train.py	19.17% <0.00%> (ø)
mmcls/core/optimizers/__init__.py	100.00% <ø> (ø)
mmcls/core/visualization/__init__.py	100.00% <ø> (ø)
mmcls/core/visualization/image.py	86.32% <ø> (ø)
mmcls/models/backbones/conformer.py	98.18% <ø> (ø)
mmcls/models/backbones/repvgg.py	96.84% <ø> (ø)
mmcls/models/utils/augment/utils.py	100.00% <ø> (ø)
mmcls/datasets/builder.py	90.62% <100.00%> (ø)

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[Ezra-Yu]

LGTM.