Missing qualifier for `project_dir`

[ph-kev]

For the calibrate function, project_dir should be ClimaCalibrate.project_dir since project_dir is not defined in this module. I found this bug from trying to update the ClimaCoupler calibration pipeline to use the main branch of ClimaCalibrate.

ClimaCalibrate.jl/src/calibration.jl

Lines 40 to 48 in 7fd54c0

	function calibrate(
	backend::HPCBackend,
	ekp::EKP.EnsembleKalmanProcess,
	n_iterations,
	prior,
	output_dir,
	model_interface;
	experiment_dir = project_dir(),
	exeflags = "",

[ph-kev]

With #312 merged, this isn't an issue anymore.