add CI qualifier to push docs for new tags

[mattip]

In addition to pushing nightly docs, also push docs with a tag. The script that pushes is already primed for this, just the trigger was missing.

@brianjo

[codecov]

Codecov Report

Merging #3373 (2ccd654) into master (61e00d5) will decrease coverage by 0.02%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master    #3373      +/-   ##
==========================================
- Coverage   74.83%   74.80%   -0.03%     
==========================================
  Files         105      105              
  Lines        9722     9716       -6     
  Branches     1563     1561       -2     
==========================================
- Hits         7275     7268       -7     
- Misses       1960     1961       +1     
  Partials      487      487              

Impacted Files	Coverage Δ
torchvision/datasets/utils.py	70.43% <0.00%> (-0.54%)	⬇️
torchvision/ops/boxes.py	87.35% <0.00%> (-0.43%)	⬇️
torchvision/models/detection/backbone_utils.py	88.05% <0.00%> (-0.35%)	⬇️
torchvision/transforms/functional.py	81.73% <0.00%> (-0.05%)	⬇️

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[fmassa]

Thanks!