Attachment size limited to 256MB #1293

Describe the bug
I am unable to upload attachments larger than 256MB (according to the error).

Steps To Reproduce

1. Running Ubuntu 18.04 - used installation script
2. updated /etc/php/7.2/apache2/php.ini

memory_limit = 2048M
post_max_size = 2048M
upload_max_filesize = 2048M

3. Go to any page and try an upload file larger that 256MB
   4: Get error "File is too big (filesize). Max filesize: 256MiB."

Screenshots

Configuration:

• BookStack v0.25.1
• PHP Version: 7.2.15
• Apache 2