Install missing ruby-scanf package

If not present, when this image breaks when compiling catalogues:

    Compiling catalog for profile::puppet::server...
    Error: Could not call 'find' on 'catalog': No content type in http response; cannot parse
    Error: Could not call 'find' on 'catalog': No content type in http response; cannot parse
    Error: Try 'puppet help catalog download' for usage

Dockerfile

@@ -2,7 +2,12 @@ FROM debian:bullseye
 
 HEALTHCHECK --interval=10s --timeout=15s --retries=12 --start-period=3m CMD ["/usr/bin/curl", "-k", "-I", "https://127.0.0.1:8140"]
 
-RUN apt-get update -qq && apt install -y git puppet-master curl augeas-tools
+RUN apt-get update -qq && apt install -y \
+	augeas-tools \
+	curl \
+	git \
+	puppet-master
+	ruby-scanf
 RUN puppet config set autosign "true" --section master
 
 COPY entrypoint.sh /