fix(doc): php version 8.1 starting support form monica v4.0.0

[alaa-alsalehi]

Documentation issue

All document mention that PHP version is 8.1 and tag mention in document 2.18.0 which was on old version so the composer will not work right I suggest modifing the docs to tag 4.0.0 at least which is the first version have 8.1 version

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[asbiin]

We won't update the tag in the doc on each tag creation. Thank you.

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