bpo-43651: PEP 597: Fix pdeps used locale encoding (GH-25204)

diff --git a/Tools/scripts/pdeps.py b/Tools/scripts/pdeps.py
index 4e8e930..ab0040f 100755
--- a/Tools/scripts/pdeps.py
+++ b/Tools/scripts/pdeps.py
@@ -64,7 +64,7 @@ def main():
 # Collect data from one file
 #
 def process(filename, table):
-    with open(filename) as fp:
+    with open(filename, encoding='utf-8') as fp:
         mod = os.path.basename(filename)
         if mod[-3:] == '.py':
             mod = mod[:-3]