Add link to TorchIO tutorial in PyTorch Ecosystem examples

[fepegar]

What does this PR do?

Resolves #7595.

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[carmocca]

Awesome project!

[codecov]

Codecov Report

Merging #7612 (ab917d7) into master (7cdf036) will decrease coverage by 5%.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master   #7612    +/-   ##
=======================================
- Coverage      92%     88%    -5%     
=======================================
  Files         197     197            
  Lines       12878   12874     -4     
=======================================
- Hits        11896   11312   -584     
- Misses        982    1562   +580     

[fepegar]

Thanks for reviewing, @carmocca, @ananthsub and @awaelchli.

For the record, I updated the changelog following the Geometric example: https://github.com/PyTorchLightning/pytorch-lightning/blob/master/CHANGELOG.md#added-9