Use caret (`^`) comparison instead of `==` for `required_version`

[wesleymatosdev]

So, for context, we had only a text comparison for required_version param. Then, on #6066 I introduced semver library so we didn't had to fix this ourselves nor maintain this complexity on this codebase.

One thing tho, is that the only values available for required_version at the time, were exact versions, which would generate an exact match. Which means we were not semver-compliant.

At the time, as this made sense for me to not break change the implementation, we should use == as the default behavior, instead of ^ when there is no operator on it. Because of that, I even opened dtolnay/semver#311 asking semver maintainer to include the option to use other default operator.

The thing is, a few days ago the issue was closed, with this justification:

This diverges from how version requirements with no comparison operator are treated by Cargo.
source: dtolnay/semver#311 (comment)

After digging a bit on that, according to The Cargo Book:

Caret requirements are the default version requirement strategy. This version strategy allows SemVer compatible updates. They are specified as version requirements with a leading caret (^).
source: https://doc.rust-lang.org/cargo/reference/specifying-dependencies.html#caret-requirements

With this information, it makes sense to make this semver-compliant and follow the default Cargo behavior.

TL;DR: We should do the same as cargo does and use ^ as the default comparator instead of == which was used to kept the behavior from before we introduced semver-compliant behavior with semver library.

[wesleymatosdev]

@ytmimi lmk what you think about this, if you feel it makes sense, I'll create the PR.