[3.20] main/py3-setuptools: fix secfixes to match actual version

👋 Hi @kdaudt!

It looks like in this commit (7d5818fe ) the version 70.3.0 for py3-setuptools was changed to -> 70.3.0-rc0 by mistake. rc0 should be r0

I think this is an invalid constraint and should be updated to 70.3.0-r0.

Here is the merge request it was originally found in: !69444 (merged)

Branches for 3.19, 3.18 and 3.17 use the correct format for reference:

• 3.19
• 3.18
• 3.17