Fix mach string type

[vitormattos]

[vitormattos]

@byjg what can we do to complete this PR?

[byjg]

This major upgrade needs to be replicated to the other components related to Swagger Test. Here you can the class diagram.

It means, Swagger Test requires directly:

• Webrequest
• Restserver

and these depend on:

• URI
• Serializer
• Singleton
• Cache

This is the minimal before have Swagger Test PHP 8.0 exclusively. After that, I can migrate the others that depend on the components above like anydataset-db, micro-orm, mailwrapper, etc.

I was planning to create a major upgrade and migrate all of them to a new 5.0.0 version and create a framework name for them, but I still have to develop with caution.

[vitormattos]

anyway, I'm using this branch in LibreSign and it's working without problems.

[byjg]

In fact, you don't need to upgrade. The issue avoiding running on PHP 8.0 was fixed in #64. Version 3.1.4 will run normally on PHP 8.0.