Use pre-install command to install jupyter_client

pyproject.toml

@@ -30,7 +30,7 @@ dependencies = [
     "anyio>=3.1.0",
     "argon2-cffi",
     "jinja2",
-    "jupyter_client@git+https://github.com/davidbrochart/jupyter_client#egg=external-kernels",
+    "jupyter_client>=7.4.4",
     "jupyter_core>=4.12,!=5.0.*",
     "jupyter_server_terminals",
     "nbconvert>=6.4.4",
@@ -90,16 +90,16 @@ docs = [
 [project.scripts]
 jupyter-server = "jupyter_server.serverapp:main"
 
-[tool.hatch.metadata]
-allow-direct-references = true
-
 [tool.hatch.envs.docs]
 features = ["docs"]
 [tool.hatch.envs.docs.scripts]
 build = "make -C docs html SPHINXOPTS='-W'"
 api = "sphinx-apidoc -o docs/source/api -f -E jupyter_server */terminal jupyter_server/pytest_plugin.py"
 
 [tool.hatch.envs.test]
+pre-install-commands = [
+  "pip install https://github.com/davidbrochart/jupyter_client/archive/external-kernels.zip"
+]
 features = ["test"]
 [tool.hatch.envs.test.scripts]
 test = "python -m pytest -vv {args}"
@@ -112,6 +112,9 @@ dependencies = [ "mypy>=0.990" ]
 test = "mypy --install-types --non-interactive {args:.}"
 
 [tool.hatch.envs.cov]
+pre-install-commands = [
+  "pip install https://github.com/davidbrochart/jupyter_client/archive/external-kernels.zip"
+]
 features = ["test"]
 dependencies = ["coverage[toml]", "pytest-cov"]
 [tool.hatch.envs.cov.scripts]