fix: add missing idn2 package to debian image

Dockerfile.debian

@@ -11,6 +11,7 @@ RUN apt-get update && apt-get install -y \
   jq \
   openssh-client \
   unzip \
+  idn2 \
   && rm -rf /var/lib/apt/lists/*
 
 # NOTE: cosign is not yet available in the debian apt sources