Add configuring hashing func

via SF_NOTIFIER_ALERT_ID_HASH_FUNC env var

Change-Id: I7c4a2592a85825d75fe0c18c18789fcfc3d0ceff
Related-bug: PROD-25673 (PROD:25673)
diff --git a/sf_notifier/server.py b/sf_notifier/server.py
index e9414bc..ba1017f 100644
--- a/sf_notifier/server.py
+++ b/sf_notifier/server.py
@@ -42,7 +42,10 @@
 
 @app.route('/info', methods=['GET'])
 def info():
-    return jsonify({'version': settings.VERSION})
+    return jsonify({
+        'version': settings.VERSION,
+        'hashing': sf_cli.hash_func.__name__
+    })
 
 
 @app.route('/hook', methods=['POST'])