Endpoints for retainers.
GETReturns retainers for the specified project.
/projects/{projectId}/retainersPOSTCreates a retainer for the specified project./projects/{projectId}/retainersGETReturns the specified project retainer./projects/{projectId}/retainers/{retainerId}PUTUpdates the specified project retainer./projects/{projectId}/retainers/{retainerId}DELETEDeletes a retainer from the specified project./projects/{projectId}/retainers/{retainerId}