Install xdebug 3 in Docker container

Dockerfile

# https://matthewsetter.com/setup-step-debugging-php-xdebug3-docker/
# ENV XDEBUG_PORT 9000
# ENV XDEBUG_IDEKEY docker

RUN set eux; \
    pecl install "xdebug"; \
    docker-php-ext-enable xdebug; \
    rm -r /tmp/pear; \
    { \
        echo "xdebug.mode=debug"; \
        echo "xdebug.start_with_request=yes"; \
        echo "xdebug.client_host=host.docker.internal"; \
        echo "xdebug.client_port=${XDEBUG_PORT}"; \
        echo "xdebug.idekey=${XDEBUG_IDEKEY}"; \
        echo "xdebug.log=/tmp/xdebug.log"; \
    } > $PHP_INI_DIR/conf.d/xdebug.ini