fix: add UTF-8 encoding to file open operation

This fixes the lint-python-utf8-encoding.py linter failure by explicitly
specifying encoding='utf8' when opening the GITHUB_OUTPUT file.

Author: PastaPastaPasta

.github/workflows/handle_potential_conflicts.py

@@ -60,7 +60,7 @@ def set_github_output(name, value):
         return
 
     try:
-        with open(os.environ['GITHUB_OUTPUT'], 'a') as f:
+        with open(os.environ['GITHUB_OUTPUT'], 'a', encoding='utf8') as f:
             # For multiline values, use the delimiter syntax
             if '\n' in str(value):
                 delimiter = f"EOF_{uuid.uuid4()}"