As a user, I want to be able to get all Test Runs modified until an specific date when using the GraphQL getTestRuns request.

As a user, I want to be able to get all Test Runs modied until an specific date when using the GraphQL getTestRuns request. 

Currently, the GraphQL getTestRuns request have a "modifiedSince" parameter, that allows us to get all test runs modified since a given date. 

A new parameter: "modifiedUntil" should be included, so we can get all test runs modifed until the given date.

Both parameters should be able to be used simultaneously.