Upgrade to Debian 11.9 (#440)

See: https://www.debian.org/News/2024/2024021002

Signed-off-by: Wouter Born <[email protected]>

Author: wborn

debian/Dockerfile

@@ -1,4 +1,4 @@
-FROM debian:11.8-slim
+FROM debian:11.9-slim
 
 ARG BUILD_DATE
 ARG VCS_REF