Merge dev-1.x to 1.x

[ly015]

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Motivation

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Modification

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BC-breaking (Optional)

Does the modification introduces changes that break the back-compatibility of this repo?
If so, please describe how it breaks the compatibility and how users should modify their codes to keep compatibility with this PR.

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Checklist

1. Pre-commit or other linting tools should be used to fix the potential lint issues.
2. The modification should be covered by complete unit tests. If not, please add more unit tests to ensure the correctness.
3. If the modification has potential influence on downstream projects, this PR should be tested with downstream projects, like MMDet or MMCls.
4. The documentation should be modified accordingly, like docstring or example tutorials.

[codecov]

Codecov Report

Base: 75.99% // Head: 76.15% // Increases project coverage by +0.16% 🎉

Coverage data is based on head (d24701c) compared to base (215378c).
Patch coverage: 75.27% of modified lines in pull request are covered.

Additional details and impacted files

@@            Coverage Diff             @@
##              1.x    #2217      +/-   ##
==========================================
+ Coverage   75.99%   76.15%   +0.16%     
==========================================
  Files         151      157       +6     
  Lines       11376    12121     +745     
  Branches     1881     1997     +116     
==========================================
+ Hits         8645     9231     +586     
- Misses       2298     2429     +131     
- Partials      433      461      +28     

Flag	Coverage Δ
unittests	76.15% <75.27%> (+0.16%)	⬆️

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

Impacted Files	Coverage Δ
mmaction/engine/hooks/visualization_hook.py	30.61% <0.00%> (ø)
...ptimizers/layer_decay_optim_wrapper_constructor.py	19.64% <19.64%> (ø)
mmaction/models/backbones/mvit.py	78.81% <26.47%> (-5.26%)	⬇️
mmaction/models/heads/timesformer_head.py	81.81% <33.33%> (-18.19%)	⬇️
mmaction/datasets/transforms/loading.py	81.22% <41.66%> (+0.32%)	⬆️
mmaction/visualization/action_visualizer.py	70.19% <45.45%> (+2.23%)	⬆️
mmaction/datasets/activitynet_dataset.py	45.45% <50.00%> (ø)
mmaction/datasets/repeat_aug_dataset.py	75.86% <60.00%> (-8.14%)	⬇️
...maction/apis/inferencers/actionrecog_inferencer.py	74.07% <74.07%> (ø)
mmaction/apis/inference.py	44.57% <75.00%> (+0.82%)	⬆️
... and 28 more

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