automation: remove python-dev from unstable-arm64v8.dockerfile

[Stefano Stabellini]

Debian unstable doesn't have the legacy python-dev package anymore.

Signed-off-by: Stefano Stabellini <stefano.stabell...@xilinx.com>

diff --git a/automation/build/debian/unstable-arm64v8.dockerfile 
b/automation/build/debian/unstable-arm64v8.dockerfile
index 4409f596e1..5c73458d9d 100644
--- a/automation/build/debian/unstable-arm64v8.dockerfile
+++ b/automation/build/debian/unstable-arm64v8.dockerfile
@@ -15,7 +15,6 @@ RUN apt-get update && \
         zlib1g-dev \
         libncurses5-dev \
         libssl-dev \
-        python-dev \
         python3-dev \
         xorg-dev \
         uuid-dev \