rollbar-php v0.9.1 released

Version 0.9.1 of rollbar-php has been released, addressing a specific issue encountered when using rollbar-php with the rollbar-agent for asynchronous reporting. Previously, the agent mode created blank files on each request regardless of whether there was anything to report, but the update ensures these files are only generated when necessary. The update is available on Packagist and GitHub, with special thanks to Ryan Fink from Red Ventures for the fix.