releasing 0.5.3

[wyli]

Is your feature request related to a problem? Please describe.
this is a minor version release to provide non-breaking fixes of a few known issues,
and to test out the new branching model/release procedure.

this ticket will be used for tracking any issues during the release.

see also:
#2041

[wyli]

just two notes that:

• The original gitflow always tags the latest commit on 'main'. This is not compatible with MONAI's versioning which uses git describe to compute the version number from a tag. So, we tag the latest commit on the release branch and then merge the commit to both 'main' and 'dev'.
• For the same reason, we couldn't use the repo's "squash and merge" approach to handle the tagging commit. I'll manually merge the released commits back to 'main and 'dev' in order to preserve the tagging information on both branches.