`strip_string_quotes` should be enabled by default

[guillermojp]

I think strip_string_quotes should be True by default to avoid unforeseen changes with regards to versions below 8.x.

In my use case, I was using this in my CI/CD, and this caused quotes to be propagated and to break existing functionality.

It's essentially my fault because I didn't have a static version for the python-hcl2 package, but it might still be worthwhile to add as an issue here.

Thanks! 😄

[kkozik-amplify]

We've decided to set strip_string_quotes to False by default for content fidelity and disambiguity. For example, after parsing a list containing both strings and integers (or floats, or plain identifiers or bools) to JSON, you can't tell which one is which. This is also crucial in JSON -> HCL2 reverse transformation.

FWIW, there's a migration guide.

(edit - I'll keep this issue open for visibility)