Re-enable link checking on www.ecmwf.int

[trexfeathers]

📚 Documentation

#5088 temporarily disabled link checking for www.ecmwf.int, since this was blocking CI and there seemed to be no problem with humans clicking the link. We should remove this exception in future and see if the CI passes.

iris/docs/src/conf.py

Lines 367 to 368 in 7e15882

	# TODO: try removing this again in future - was raising an SSLError.
	"http://www.ecmwf.int/",

[trexfeathers]

Try HTTPS