Installer: require curl, openssl and pcre
Installer: require curl, openssl and pcre

The CLI won't work at all without the pcre or openssl extensions, so making this check required won't break BC.

Without the curl extension, most requests will still work, but it's more maintainable just to require it. Manual installation can still bypass this check.

pjcdawkins/platformsh-cli,platformsh/platformsh-cli,platformsh/platformsh-cli,pjcdawkins/platformsh-cli,pjcdawkins/platformsh-cli,platformsh/platformsh-cli