feat: insta for snapshot testing

[vasucp1207]

Related to https://github.com/obi1kenobi/cargo-semver-checks/issues/634

[!WARNING]
This is just for checking how to update snapshots with insta. Not a migration from the current test system to insta snapshots.

Trying out the insta for snapshot testing and find out that moving to insta is not a big deal we just have to adjust the current testing logic. Run cargo-test and cargo-insta-accept, snapshots will created in src/snapshots with ron format. No need for manually paste the diff.

cc @obi1kenobi