Require the curl extension in composer.json

[jenssegers]

I would also add a minimum PHP requirement.

[coryvirok]

Thanks for the PR @jenssegers. PHP isn't my primary language so can you help me understand the need and any potential downsides for this change?

Thanks!

[jenssegers]

This will warn users that try to install rollbar when they do not have the curl extension installed. You can do the same thing with a minimum PHP requirement, that will inform them if their PHP version is outdated if you are using specific version features.

[jenssegers]

I did the same PR on Sentry's client: getsentry/raven-php@6faf446

[coryvirok]

Gotcha. Thanks for the info.

[brianr]

Thanks @jenssegers !