Generate Better Index Keys (#3826)

* Generate Better Index Keys

* More Robust index mapping

* Remove unused import

* Remove unused import

---------

Co-authored-by: Terrance DeJesus <99630311+terrancedejesus@users.noreply.github.com>
Co-authored-by: Mika Ayenson <Mikaayenson@users.noreply.github.com>

(cherry picked from commit 949ceccc0f)

detection_rules/packaging.py

@@ -246,7 +246,6 @@ class Package(object):
 
     def generate_summary_and_changelog(self, changed_rule_ids, new_rule_ids, removed_rules):
         """Generate stats on package."""
-        from string import ascii_lowercase, ascii_uppercase
 
         summary = {
             'changed': defaultdict(list),
@@ -261,7 +260,7 @@ class Package(object):
             'unchanged': defaultdict(list)
         }
 
-        # build an index map first
+        # Build an index map first
         longest_name = 0
         indexes = set()
         for rule in self.rules:
@@ -270,8 +269,7 @@ class Package(object):
             if index_list:
                 indexes.update(index_list)
 
-        letters = ascii_uppercase + ascii_lowercase
-        index_map = {index: letters[i] for i, index in enumerate(sorted(indexes))}
+        index_map = {index: str(i) for i, index in enumerate(sorted(indexes))}
 
         def get_summary_rule_info(r: TOMLRule):
             r = r.contents