Github Host key verification Failing – Magento

I am trying to add Github.com as known_hosts file for this docker file but somehow I believe www-data is failing to get access to known_hosts file. Code below is the complete docker file. Specific git error is

Failed to execute git clone –mirror —

Host key verification failed.
fatal: Could not read from remote repository.

Please make sure you have the correct access rights.

and the repository exists.

   FROM php:7.4-fpm as base
    ENV COMPOSER_HOME=/tmp/composer
    ENV APCU_VERSION=5.1.18
    
    RUN apt-get update && apt-get install -y --no-install-recommends gnupg 
        netcat 
        sudo 
        libicu-dev 
        libfreetype6-dev 
        libjpeg-dev 
        libpng-dev 
        libsodium-dev 
        libxml2-dev 
        libxslt-dev 
        libzip-dev 
        rsync 
        unzip 
        git 
        openssh-client 
        ;
    
    RUN pecl install apcu-${APCU_VERSION}
    
    RUN docker-php-ext-configure gd --enable-gd --with-freetype --with-jpeg
    RUN docker-php-ext-install -j "$(nproc)" 
        bcmath 
        gd 
        intl 
        mysqli 
        opcache 
        pdo_mysql 
        sockets 
        soap 
        xsl 
        zip 
        ;
    
    RUN docker-php-ext-enable apcu
    
    RUN echo "memory_limit=1G" >> /usr/local/etc/php/conf.d/zz-memory-limit-php.ini
    RUN echo "apc.enable=1" >> /usr/local/etc/php/conf.d/zz-apcu.ini
    RUN echo "apc.enable_cli=1" >> /usr/local/etc/php/conf.d/zz-apcu.ini
    RUN echo "opcache.memory_consumption=512MB" >> /usr/local/etc/php/conf.d/zz-opcache.conf
    RUN echo "opcache.max_accelerated_files=60000" >> /usr/local/etc/php/conf.d/zz-opcache.conf
    RUN echo "opcache.consistency_checks=0" >> /usr/local/etc/php/conf.d/zz-opcache.conf
    RUN echo "opcache.validate_timestamps=0" >> /usr/local/etc/php/conf.d/zz-opcache.conf
    RUN echo "opcache.enable_cli=1" >> /usr/local/etc/php/conf.d/zz-opcache.conf
    
    
    FROM base as build
    
    RUN curl https://files.magerun.net/n98-magerun2.phar -o /usr/local/bin/magerun 
        && chmod 755 /usr/local/bin/magerun
    RUN mkdir -p /root/.ssh && 
        chmod 0700 /root/.ssh && 
        ssh-keyscan -t rsa github.com >> /root/.ssh/known_hosts
    USER www-data
    WORKDIR /var/www/html
    
    ARG COMPOSER_AUTH
    
    COPY --from=composer:2 /usr/bin/composer /usr/bin/composer
    
    COPY --chown=www-data composer.json composer.json
    COPY --chown=www-data composer.lock composer.lock
    
    RUN php -d memory_limit=2G $(which composer) install --no-progress --no-dev
    
    COPY --chown=www-data app/etc/config.php app/etc/config.php
    
    COPY --chown=www-data bin bin
    
    FROM build as app
    
    ENV MAGE_MODE=production
    RUN php -d memory_limit=2G bin/magento setup:di:compile
    RUN composer dump-autoload --optimize --apcu
    RUN php -d memory_limit=2G bin/magento setup:static-content:deploy -f
    RUN rm -rf /var/www/html/var/cache
    RUN rm -rf /var/www/html/var/page_cache
    RUN rm -rf /var/www/html/var/session
    
    COPY --chown=www-data app/etc/env.docker.php app/etc/env.php