Add inotify-tools to build environment

[killenheladagen]

inotify-wait is handy when modifying a file outside the container and letting that trigger a new build inside it.

Checklist before requesting a review

• I have performed a self-review of my own code
• I have verified that the code builds perfectly fine on my local system
• I have added tests that prove my fix is effective or that my feature works
• I have commented my code, particularly in hard-to-understand areas
• I have verified that my code follows the style already available in the repository
• I have made corresponding changes to the documentation