feat: adding support for rails 6 and 7

[HassanAkbar]

Upgraded to support Rails 6 and Rails 7

resolves #72

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Error: unrecognized cop Rails found in .rubocop.yml, unrecognized cop Rails/A...

Error: unrecognized cop Rails found in .rubocop.yml, unrecognized cop Rails/ApplicationRecord found in .rubocop.yml

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Some files could not be reviewed due to errors:

Error: unrecognized cop Rails found in .rubocop.yml, unrecognized cop Rails/A...

Error: unrecognized cop Rails found in .rubocop.yml, unrecognized cop Rails/ApplicationRecord found in .rubocop.yml

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Error: unrecognized cop Performance/CaseWhenSplat found in .rubocop.yml, unre...

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[HassanAkbar]

@ronaldtse the jruby test cases for postgresql are failing and I think that is because of this issue in jruby itself when using UUIDs jruby/activerecord-jdbc-adapter#1086

I will look into it further but if this is the cause of the issue then what do you suggest we do until the issue is fixed?