ci: fix LIBCLANG_PATH detection on Ubuntu

dpkg -L libclang-dev returns no library files because libclang-dev is a
meta-package on Ubuntu 22.04. Use find over /usr/lib/llvm-*/lib instead,
which works regardless of the installed LLVM version.

Author: nicolasayotte

.github/workflows/ci.yml

@@ -27,7 +27,7 @@ jobs:
 
       - name: Set LIBCLANG_PATH
         run: |
-          LIBCLANG_DIR=$(dirname "$(dpkg -L libclang-dev | grep libclang.so$ | head -1)")
+          LIBCLANG_DIR=$(dirname "$(find /usr/lib/llvm-*/lib -name 'libclang.so' 2>/dev/null | sort -V | tail -1)")
           echo "LIBCLANG_PATH=$LIBCLANG_DIR" >> "$GITHUB_ENV"
 
       - uses: dtolnay/rust-toolchain@stable