Releasing OCP 7.9

[Oblynx]

Hey, thanks for adding support for OCP 7.9 in January!

When you made the latest cadquery release, you weren't yet confident to release OCP 7.9 support. In the 4 months that followed, I don't see any major issues having popped up specifically related to OCP 7.9 and from the PR log it looks like the implementation is also stable.

Would you consider releasing OCP 7.9 support soon?

[Oblynx]

At the time of the 2.7.0 release, we had this discussion with @jmwright that OCP 7.9 needs more quality assurance.

[adam-urbanczyk]

7.9 is well tested by now. I think we are going to make a release in June.