deps: add holidays library to requirements

UntisSync · UntisSync · commit 130e7bad825e · 2025-11-09T21:36:26.000Z
diff --git a/requirements.txt b/requirements.txt
@@ -3,3 +3,4 @@ google-auth-httplib2>=0.1.1
 google-auth-oauthlib>=1.1.0
 selenium>=4.15.0
 python-dotenv>=1.0.0
+holidays>=0.84
