swap toml with tomli

setup.py

@@ -41,7 +41,15 @@
         "Programming Language :: Python :: Implementation :: PyPy",
     ],
     use_incremental=True,
-    install_requires=["click", "click-default-group", "incremental", "jinja2", "setuptools", "toml"],
+    install_requires=[
+        "click",
+        "click-default-group",
+        "incremental",
+        "jinja2",
+        "setuptools",
+        "toml; python_version < '3.6'",
+        "tomli; python_version > '3.6'",
+    ],
     extras_require={"dev": ["packaging"]},
     package_dir={"": "src"},
     packages=find_packages("src"),

src/towncrier/_settings.py

@@ -1,9 +1,15 @@
 # Copyright (c) Amber Brown, 2015
 # See LICENSE for details.
 
+import io
 import os
+import sys
 import pkg_resources
-import toml
+
+if sys.version_info > (3, 5):
+    from tomli import load as _toml_load
+else:
+    from toml import load as _toml_load
 
 from collections import OrderedDict
 
@@ -69,8 +75,8 @@ def load_config(directory):
 
 def load_config_from_file(directory, config_file):
 
-    with open(config_file, "r") as conffile:
-        config = toml.load(conffile)
+    with open(config_file, "r", encoding="utf8") as conffile:
+        config = _toml_load(conffile)
 
     return parse_toml(directory, config)