Update Dockerfile

Author: hoodadt

contrib/Dockerfile

@@ -1,4 +1,4 @@
-FROM alpine:3.22.1 AS builder
+FROM alpine:latest AS builder
 
 RUN apk add --no-cache \
   build-base \
@@ -10,16 +10,19 @@ COPY ./ /app
 WORKDIR /app
 RUN autoreconf --install && ./configure && make
 
-FROM alpine:3.22.1
+FROM alpine:latest
 
 # OCI annotations
 LABEL org.opencontainers.image.title="fping" \
       org.opencontainers.image.authors="fping Community" \
       org.opencontainers.image.description="High performance ping tool" \
-      org.opencontainers.image.base.name="docker.io/library/alpine:3.22.1" \
+      org.opencontainers.image.base.name="docker.io/library/alpine:latest" \
       org.opencontainers.image.source="https://github.com/schweikert/fping" \
       org.opencontainers.image.documentation="https://fping.org/fping.8.html"
 
+RUN apk add --no-cache mandoc
+
 COPY --from=builder /app/src/fping /usr/local/bin/fping
+COPY --from=builder /app/doc/fping.8 /usr/share/man/man8/fping.8
 
 ENTRYPOINT ["fping"]