Update securitychecker.md

[wannevancamp]

securitychecker_roave was missing in the Security Checker list

Q	A
Branch	master for features and deprecations
Bug fix?	yes/no
New feature?	yes/no
BC breaks?	yes/no
Deprecations?	yes/no
Documented?	yes/no
Fixed tickets	comma-separated list of tickets fixed by the PR, if any

New Task Checklist:

• [ ] Are the dependencies added to the composer.json suggestions?
• [ ] Is the doc/tasks.md file updated?
• [ ] Are the task parameters documented?
• [ ] Is the task registered in the tasks.yml file?
• [ ] Does the task contains phpunit tests?
• [ ] Is the configuration having logical allowed types?
• [ ] Does the task run in the correct context?
• [ ] Is the run() method readable?
• [ ] Is the run() method using the configuration correctly?
• [ ] Are all CI services returning green?

[veewee]

Thanks!