Update Dockerfile label to opencontainers format

Author: andyone

Dockerfile

@@ -18,11 +18,13 @@ RUN apk add --no-cache git make upx && \
 
 FROM essentialkaos/alpine:3.13
 
-LABEL name="SSLCLI Image" \
-      vendor="ESSENTIAL KAOS" \
-      maintainer="Anton Novojilov" \
-      license="Apache-2.0" \
-      version="2021.12.10"
+LABEL org.opencontainers.image.title="sslcli" \
+      org.opencontainers.image.description="Pretty awesome command-line client for public SSLLabs API" \
+      org.opencontainers.image.vendor="ESSENTIAL KAOS" \
+      org.opencontainers.image.authors="Anton Novojilov" \
+      org.opencontainers.image.licenses="Apache-2.0" \
+      org.opencontainers.image.url="https://kaos.sh/sslcli" \
+      org.opencontainers.image.source="https://github.com/essentialkaos/sslcli"
 
 COPY --from=builder /go/src/github.com/essentialkaos/sslcli/sslcli /usr/bin/