Support Ghidra 12.0

[0dinD]

Ghidra 12.0 has been released: https://github.com/NationalSecurityAgency/ghidra/releases/tag/Ghidra_12.0_build

It notably contains a fix for NationalSecurityAgency/ghidra#570, which should mean that we can remove this:

Ps3GhidraScripts/README.md

Lines 21 to 24 in 7600ac4

	## Required change
	To avoid issues with decompilation the following change is needed in `Ghidra\Processors\PowerPC\data\languages\ppc_64_32.cspec`
	Add `<register name="r2"/>` to the `<unaffected>` list

[clienthax]

Added to CI, please test if r2 fix is still needed.