Bypass PECL ssl connection in Docker

I need to mantain a legacy sowftware, developing with docker with Jessie php:7.0.17-fpm.

I need to install a software from PECL but I get:

#0 2.359 WARNING: channel "pecl.php.net" has updated its protocols, use "pecl channel-update pecl.php.net" to update
#0 2.596 Could not download from "https://pecl.php.net/get/oci8-2.1.3.tgz", cannot download "pecl/oci8" (Connection to `ssl://pecl.php.net:443' failed: )
#0 2.596 Error: cannot download "pecl/oci8"
#0 2.597 Download failed
#0 2.597 install failed

And this is the relevant section of Docker:

# Install Oracle extensions
RUN pecl channel-update pecl.php.net pecl update-channels; rm -rf /tmp/pear ~/.pearrc
RUN echo 'instantclient,/opt/oracle/instantclient_12_1/' | pecl install oci8-2.1.3  
      && docker-php-ext-enable 
               oci8  
       && docker-php-ext-configure pdo_oci --with-pdo-oci=instantclient,/opt/oracle/instantclient_12_1,12.1 
       && docker-php-ext-install 
               pdo_oci

I’m lookig for a mode to skip the SSL check. It is an internal image.

I added as requested from PECL RUN pecl channel-update pecl.php.net pecl update-channels; rm -rf /tmp/pear ~/.pearrc but I cannot solve.

Thank you