config: fix linting warnings

scripts/config.sh

@@ -19,7 +19,7 @@ versions_file=versions.md
 row="$(grep "^| $version " "$versions_file")"
 
 if [ -z "$row" ]; then
-    printf "Unknown or unsupported version '%s'\n" "$version"
+    printf 'Unknown or unsupported version "%s"\n' "$version"
     exit 1
 fi
 
@@ -41,19 +41,19 @@ case "${build_stack}" in
         base_image_version="$(field 4)"
         ;;
     (*)
-        printf "Unsupported base image: '%s'\n" "$base_image"
+        printf 'Unsupported base image: "%s"\n' "$base_image"
         ;;
 esac
 
 version_tags="$(field 2)"
 tags=
 for name in $(printf '%s\n' "$images" | tr ',' ' '); do
     image_tags_base="$( \
-        printf "$version_tags" | sed -e "s#\([^,]*\)#${name}:\1#g" \
+        printf '%s\n' "$version_tags" | sed -e "s#\([^,]*\)#${name}:\1#g" \
     )"
     image_tags="$(printf '%s' "$image_tags_base" | \
                     sed -e 's#\([^,]*\)#\1-'${base_image}'#g')"
-    image_name=$(printf "$name" | sed -e 's#.*\([^/]\+/[^/]\+\)$#\1#')
+    image_name=$(printf '%s\n' "$name" | sed -e 's#.*\([^/]\+/[^/]\+\)$#\1#')
     if ( [ "$image_name" != 'pandoc/minimal' ] && \
          [ "$build_stack" = 'alpine' ] ) ||
        ( [ "$image_name"  = 'pandoc/minimal' ] && \