Click downgrade of pin below 7.1 can be removed

This application has `click` pinned to below 7.1 because of this issue: https://github.com/dbcli/mssql-cli/issues/437. The pin was done in this PR: https://github.com/dbcli/mssql-cli/pull/440

Since then `click` has issued a fix: https://github.com/pallets/click/pull/1543

We should release the pin on `click`.

In my own case I am seeing conflicts with other apps that do not have the pin. eg [maestral](https://github.com/samschott/maestral) which recently [bumped `click` to 8.0](https://github.com/SamSchott/maestral/blob/master/CHANGELOG.md#v144).