add labels on Docker image (see https://github.com/opencontainers/image-spec/blob/main/annotations.md)

Author: llaville

Dockerfile

@@ -3,9 +3,19 @@ ARG PHP_VERSION=8.3
 
 FROM php:${PHP_VERSION}-cli-alpine
 
+ARG PACKAGE_CONSTRAINT=9.5.x-dev
+
+# https://github.com/opencontainers/image-spec/blob/main/annotations.md
+
+LABEL org.opencontainers.image.title="overtrue/phplint"
+LABEL org.opencontainers.image.description="Docker image of overtrue/phplint Composer package"
+LABEL org.opencontainers.image.source="https://github.com/overtrue/phplint"
+LABEL org.opencontainers.image.licenses="MIT"
+LABEL org.opencontainers.image.authors="overtrue,llaville"
+
 COPY entrypoint.sh /entrypoint.sh
-RUN chmod +x /entrypoint.sh
-RUN cp /usr/local/etc/php/php.ini-development /usr/local/etc/php/php.ini
+RUN chmod +x /entrypoint.sh \
+    && cp /usr/local/etc/php/php.ini-development /usr/local/etc/php/php.ini
 
 # Default container directory where to mount your project source files
 # GitLab uses $CI_PROJECT_DIR to identify where job runs on source files
@@ -18,10 +28,10 @@ RUN addgroup appgroup && adduser appuser -D -G appgroup
 # Tell docker that all future commands should run as the appuser user
 USER appuser
 
-# Install Composer v2 then overtrue/phplint package
+# Install Composer v2 binary then package
 COPY --from=composer/composer:2-bin /composer /usr/bin/composer
 ENV COMPOSER_ALLOW_SUPERUSER 1
-RUN composer global require --no-progress overtrue/phplint 9.5.x-dev
+RUN composer global require --no-progress overtrue/phplint $PACKAGE_CONSTRAINT
 
 # Following recommendation at https://docs.github.com/en/actions/creating-actions/dockerfile-support-for-github-actions#workdir