refactor: unclosed file handle for readme.md (#620)

The `README.md` file is opened using `open('README.md', 'r')` but is never explicitly closed. This can lead to resource leaks, especially in long-running processes or if the script were to be extended to open many files. While Python's garbage collector might eventually close it, it's not guaranteed and is considered bad practice.

Affected files: ensure_sorted.py

Signed-off-by: toanmap <174589430+maptoan@users.noreply.github.com>

ensure_sorted.py

@@ -54,9 +54,9 @@ class Category:
         return self.__str__()
 
 def main():
-    readme_file = open('README.md', 'r')
     # start of the Apps section
     APPS_LINE_START = '## – Apps –\n'
+    with open('README.md', 'r') as readme_file:
         lines = readme_file.readlines()
 
     index: int