Ruby3, faraday2 compatibility, remove parse native collection override templates

[brunoenten]

Minor changes to bring compatibility with ruby 3 and faraday 2. Remove parse native collections models override templates that don't work.

[brunoenten]

Could you please review?

[jorgeacaballero]

Faraday2 compatibility is not met while having faraday_middleware as a dependency (see deprecation warning here: https://github.com/lostisland/faraday_middleware) if another project dependency needs faraday2 you will find the following error while bundling

parse-stack was resolved to 1.10.0, which depends on
      faraday_middleware (>= 0.9) was resolved to 0.9.0, which depends on
        faraday (< 0.9, >= 0.7.4)