Update comment

[janschoenherr]

The comment did not match the time calculation.

Proposed changes

Just a typo.

Types of changes

What types of changes does your code introduce to Phpfastcache? Put an x in the boxes that apply

• [ ] Bugfix (non-breaking change which fixes an issue)
• [ ] Improvement (non-breaking change which improves an existing code/behavior)
• [ ] Deprecated third party dependency update
• [ ] New feature (non-breaking change which adds functionality)
• [ ] Breaking change (fix or feature that would cause existing functionality to not work as expected)
• [x] Documentation/Typo/Resource update that does not involve any code modification

Agreement

I have read the CONTRIBUTING and CODING GUIDELINE docs

[Geolim4]

Nice catch, thanks !

[Geolim4]

Seems like travis pipeline is buggy again today, safe to merge with only Github CI.