relax pandas constraint,expand tox envs

pyproject.toml

@@ -18,10 +18,10 @@ classifiers = [
     'License :: OSI Approved :: Apache Software License',
     'Natural Language :: English',
     'Programming Language :: Python',
-    'Programming Language :: Python :: 3.8',
     'Programming Language :: Python :: 3.9',
     'Programming Language :: Python :: 3.10',
     'Programming Language :: Python :: 3.11',
+    'Programming Language :: Python :: 3.12',
     'Operating System :: OS Independent',
     'Intended Audience :: Science/Research',
     'Topic :: Office/Business :: Financial :: Investment',
@@ -47,7 +47,7 @@ dependencies = [
     'networkx >=2.0',
     'numexpr >=2.6.1',
     'numpy >=1.14.5',
-    'pandas >=2.0',
+    'pandas >=1.3',
     'patsy >=0.4.0',
     'python-dateutil >=2.4.2',
     'python-interface >=1.5.3',
@@ -73,7 +73,8 @@ requires = [
     'setuptools>=42.0.0',
     "setuptools_scm[toml]>=6.2",
     'wheel>=0.36.0',
-    'Cython>=0.29.21,<3',
+    'Cython>=0.29.21',
+    #    'Cython>=3',
     'oldest-supported-numpy; python_version>="3.8"',
 ]
 build-backend = 'setuptools.build_meta'
@@ -102,7 +103,8 @@ dev = [
     'flake8 >=3.9.1',
     'black',
     'pre-commit >=2.12.1',
-    'Cython>=0.29.21,<3',
+    #    'Cython>=0.29.21,<3',
+    'Cython>=0.29.21',
 ]
 docs = [
     'Cython',
@@ -176,7 +178,7 @@ exclude = '''
 [tool.tox]
 legacy_tox_ini = """
 [tox]
-envlist = py{38,39,310,311}-pandas{2}
+envlist = py{39,310}-pandas{13,14,15}, py{39,310,311,312}-pandas{20,21,22}
 isolated_build = True
 skip_missing_interpreters = True
 minversion = 3.23.0
@@ -196,7 +198,12 @@ setenv =
 changedir = tmp
 extras = test
 deps =
-    pandas2: pandas>=2.0
+    pandas13: pandas>=1.3.0,<1.4
+    pandas14: pandas>=1.4.0,<1.5
+    pandas15: pandas>=1.5.0,<1.6
+    pandas20: pandas>=2.0,<2.1
+    pandas21: pandas>=2.1,<2.2
+    pandas22: pandas>=2.2,<2.3
 
 commands =
     pytest -n 4 --reruns 5 --cov={toxinidir}/src --cov-report term  --cov-report=xml --cov-report=html:htmlcov {toxinidir}/tests