It isn't a well known Ship in the Marvel universe. There is only one interaction between the two characters in the mainstream movies; it is in the first Thor movie. Phil Asks Agent Barton to give him a report of what he sees going on in a research center.
However, as most assume, they may have a bigger back story. It's expressed in the fandom that Phil Coulson was Agent Barton and Agent Romanoffs handler. This means that Phil and Clint would have known each other a lot more than the movies let on.
There is no developmemt of it in canon because it is not canon.