Issue #9561: distutils now reads and writes egg-info files using UTF-8

instead of the locale encoding.
diff --git a/Lib/distutils/dist.py b/Lib/distutils/dist.py
index 02cd79b..8ca5b6f 100644
--- a/Lib/distutils/dist.py
+++ b/Lib/distutils/dist.py
@@ -1010,11 +1010,9 @@
     def write_pkg_info(self, base_dir):
         """Write the PKG-INFO file into the release tree.
         """
-        pkg_info = open(os.path.join(base_dir, 'PKG-INFO'), 'w')
-        try:
+        with open(os.path.join(base_dir, 'PKG-INFO'), 'w',
+                  encoding='UTF-8') as pkg_info:
             self.write_pkg_file(pkg_info)
-        finally:
-            pkg_info.close()
 
     def write_pkg_file(self, file):
         """Write the PKG-INFO format data to a file object.