We now require that Debian users install the `python3` and `python3-pip`
packages. This change lets the Python code search for `libclang.so`, which can
be located in different directories, depending on version, and is not found by
default otherwise.
Fixes#28
PiperOrigin-RevId: 254745872
Change-Id: Ia77680da2a3235c0a9518125676aa8a460e38e76