osbuilder: Fix build dependency of ubuntu rootfs with Docker

Build ubuntu rootfs with Docker failed with error:
`Unable to find libclang`

Fix this error by adding libclang-dev to the dependency.

Signed-off-by: Jitang Lei <leijitang@outlook.com>

tools/osbuilder/rootfs-builder/ubuntu/Dockerfile.in

@@ -50,6 +50,7 @@ RUN apt-get update && \
     xz-utils \
     pip \
     python3-dev \
+    libclang-dev \
     zstd && \
     apt-get clean && rm -rf /var/lib/apt/lists/&& \
     curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh -s -- -y --default-toolchain ${RUST_TOOLCHAIN}