Fix cairo rendering of color type 3 fonts
The bug fix in 448f03cf needs to be disabled for color fonts.
Here is the test case I used generated by the cairo test suite.
user-font-color.pdf.argb32.out.pdf
I don't know why the CI is failing. It is complaining about the python version.
I don't understand why clang_format is failing. When I run git clang-format
it wants to use a different style.