Fixes wrongtype error when increment has member that is null instead of being having always a value

[abdumu]

• if there was a key that has been saved with the wrong type, it gets deleted.
• any recording method should return a value, for example, a recorded country if the country is null should be saved as 'zz'
• fixes Github actions.

#this should fix issue #44

[abdumu]

I must add, that this is a non-breaking change so that it can be released as a patch version. However, future versions of laravel-visits should remove support of PHP < 8, also Laravel < 8.