[3.13] GH-137841: Open tzdata/zones file with UTF-8 encoding (GH-137872) (#141608)

Co-authored-by: Adam Turner <9087854+AA-Turner@users.noreply.github.com>

Author: miss-islington

Lib/zoneinfo/_tzpath.py

@@ -131,7 +131,8 @@ def available_timezones():
     # Start with loading from the tzdata package if it exists: this has a
     # pre-assembled list of zones that only requires opening one file.
     try:
-        with resources.files("tzdata").joinpath("zones").open("r") as f:
+        zones_file = resources.files("tzdata").joinpath("zones")
+        with zones_file.open("r", encoding="utf-8") as f:
             for zone in f:
                 zone = zone.strip()
                 if zone: