Fixed some copyright header typos

[pfc-bot]

Proposed changes

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If it fixes a bug or resolves a feature request, be sure to link to that issue.

Types of changes

What types of changes does your code introduce to Phpfastcache?
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• 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)
• Documentation/Typo/Resource update that does not involve any code modification

Agreement

I have read the CONTRIBUTING and CODING GUIDELINE docs

Further comments

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