Assume yes on apt upgrade to avoid non-interactive prompting

Author: tashian

docker/Dockerfile.debian

@@ -28,7 +28,7 @@ ARG STEPUID=1000
 ARG STEPGID=1000
 
 RUN apt-get update \
-        && apt-get upgrade \
+        && apt-get upgrade -y \
         && apt-get install -y --no-install-recommends curl \
         && addgroup --gid ${STEPGID} step \
         && adduser --disabled-password --uid ${STEPUID} --gid ${STEPGID} step