Add labels, update just helper

Dockerfile

@@ -1,9 +1,15 @@
-FROM alpine:3
+FROM docker.io/library/alpine:3
+
+LABEL org.opencontainers.image.title=jswank/alpine-cli \
+      org.opencontainers.image.description="A minimal image for running Linux CLI utilities" \
+      org.opencontainers.image.url=https://git.sr.ht/~jswank/alpine-cli \
+      org.opencontainers.image.authors="Jason Swank" \
+      org.opencontainers.image.licenses=MIT
 
 RUN apk -U --no-cache add \
-  doas doas-sudo-shim \
-  bash less \
-  coreutils grep gawk perl 
+    doas doas-sudo-shim \
+    bash less \
+    coreutils grep gawk perl 
 
 RUN adduser -h /home/cli -s /bin/bash -D cli cli && \
     addgroup cli wheel && \