update clang dependency to 1.0

[StephanvanSchaik]

This updates the clang dependency for the ritual crate from 0.20.0 to 1.0(.3). This fixes an issue for me on Gentoo where the older version of clang-sys that clang depends on, where it tries to use /usr/lib/llvm/12/lib/libclang.so (the 32-bit version) rather than /usr/lib/llvm/12/lib64/libclang.so (the 64-bit version). On distributions other than Ubuntu and Debian, the 64-bit versions of libraries may be located in /usr/lib64 or a similarly named lib64 directory.