This is to fix this error I got:
Your requirements could not be resolved to an installable set of packages.
Problem 1
- Installation request for slim/slim 3.12.3 -> satisfiable by slim/slim[3.12.3].
- slim/slim 3.12.3 requires ext-simplexml * -> the requested PHP extension simplexml is missing from your system.
To enable extensions, verify that they are enabled in your .ini files:
- /etc/php7/php.ini
- /etc/php7/conf.d/00_curl.ini
- /etc/php7/conf.d/00_iconv.ini
- /etc/php7/conf.d/00_json.ini
- /etc/php7/conf.d/00_mbstring.ini
- /etc/php7/conf.d/00_openssl.ini
- /etc/php7/conf.d/01_phar.ini
You can also run `php --ini` inside terminal to see which files are used by PHP in CLI mode.
