community/py3-sip: upgrade to 6.5.0

py3-sip was 2 major versions behind, and the last py3-qt5 package didn't build with our sip 4 package. The Python bindings for KF5 were actually unmaintained upstream and didn't build with newer sip's anymore either. I've asked upstream and they considered the whole thing black magic anyway and said it should have never been merged, and will probably remove it soon. Thus, I've disabled the bindings again, nothing made use of it yet anyway.

CC @boomanaiden154, libarcus and curaengine use sip 4 and has seen no fix or update to make it work with either sip 5 or 6. Do you still use this or have need for it? Any chance you can get upstream to support sip 6? If you need this we might introduce a sip4 package, but you'll have to maintain it since curaengine would be it's only user.