docs: update ooniapi service docs to mention maximum supported hatch version

[DecFox]

We should update the ooniapi service docs here: https://github.com/ooni/backend/tree/master/ooniapi, to explicitly mention the maximum supported hatch version for building services. This was reported by @LDiazN when trying to run services with hatch==1.14.0, which seems to not support running services.

[LDiazN]

To add a bit more context, when trying to make run (which in turn runs a hatch run ...), I was getting this error:

 File "<frozen importlib._bootstrap>", line 1387, in _gcd_import
  File "<frozen importlib._bootstrap>", line 1360, in _find_and_load
  File "<frozen importlib._bootstrap>", line 1310, in _find_and_load_unlocked
  File "<frozen importlib._bootstrap>", line 488, in _call_with_frames_removed
  File "<frozen importlib._bootstrap>", line 1387, in _gcd_import
  File "<frozen importlib._bootstrap>", line 1360, in _find_and_load
  File "<frozen importlib._bootstrap>", line 1324, in _find_and_load_unlocked
ModuleNotFoundError: No module named 'oonirun'
make: *** [Makefile:62: run] Error 1

This error disappeared after switching from hatch==1.14.0 to hatch==1.12.0 and deleting the old .venv