www/py-flask: Clean up BUILD_DEPENDS

from pyproject.toml:
[build-system]
requires = ["flit_core<4"]
build-backend = "flit_core.buildapi"

from CHANGES.rst:
- Use flit_core instead of setuptools as build backend.

Reference:	https://github.com/pallets/flask/blob/3.0.0/pyproject.toml#L46-L48
		https://github.com/pallets/flask/blob/3.0.0/CHANGES.rst#version-233
Approved by:	portmgr (blanket)
With hat:	python

www/py-flask/Makefile

@@ -11,9 +11,7 @@ WWW=		http://flask.pocoo.org/
 LICENSE=	BSD3CLAUSE
 LICENSE_FILE=	${WRKSRC}/LICENSE.rst
 
-BUILD_DEPENDS=	${PY_SETUPTOOLS} \
-		${PYTHON_PKGNAMEPREFIX}wheel>=0:devel/py-wheel@${PY_FLAVOR} \
-		${PYTHON_PKGNAMEPREFIX}flit-core>=0:devel/py-flit-core@${PY_FLAVOR}
+BUILD_DEPENDS=	${PYTHON_PKGNAMEPREFIX}flit-core>=0<4:devel/py-flit-core@${PY_FLAVOR}
 RUN_DEPENDS=	${PYTHON_PKGNAMEPREFIX}werkzeug>=3.0.0:www/py-werkzeug@${PY_FLAVOR} \
 		${PYTHON_PKGNAMEPREFIX}Jinja2>=3.1.2:devel/py-Jinja2@${PY_FLAVOR} \
 		${PYTHON_PKGNAMEPREFIX}itsdangerous>=2.1.2:security/py-itsdangerous@${PY_FLAVOR} \