fixup: Fallback to toml, not tomli, for Python 2 support

Author: hroncok

setup.cfg

@@ -42,7 +42,7 @@ install_requires =
     virtualenv!=20.0.0,!=20.0.1,!=20.0.2,!=20.0.3,!=20.0.4,!=20.0.5,!=20.0.6,!=20.0.7,>=16.0.0
     colorama>=0.4.1 ;platform_system=="Windows"
     importlib-metadata>=0.12;python_version<"3.8"
-    tomli;python_version<"3.11"
+    toml;python_version<"3.11"
 python_requires = >=2.7, !=3.0.*, !=3.1.*, !=3.2.*, !=3.3.*, !=3.4.*
 
 [options.packages.find]

src/tox/config/__init__.py

@@ -22,9 +22,13 @@
 import six
 
 if sys.version_info >= (3, 11):
-    import tomllib
+    import tomllib as toml_loader
+    toml_mode = "rb"
+    toml_encoding = None
 else:
-    import tomli as tomllib
+    import toml as toml_loader
+    toml_mode = "r"
+    toml_encoding = "UTF-8"
 
 from packaging import requirements
 from packaging.utils import canonicalize_name
@@ -309,8 +313,8 @@ def parseconfig(args, plugins=()):
 
 
 def get_py_project_toml(path):
-    with io.open(str(path), mode="rb") as file_handler:
-        config_data = tomllib.load(file_handler)
+    with io.open(str(path), mode=toml_mode, encoding=toml_encoding) as file_handler:
+        config_data = toml_loader.load(file_handler)
         return config_data