Add empty files for following days.

2022/day21.py

@@ -0,0 +1,3 @@
+# -*- encoding: utf-8 -*-
+
+import sys

2022/day22.py

@@ -0,0 +1,3 @@
+# -*- encoding: utf-8 -*-
+
+import sys

2022/day23.py

@@ -0,0 +1,3 @@
+# -*- encoding: utf-8 -*-
+
+import sys

2022/day24.py

@@ -0,0 +1,3 @@
+# -*- encoding: utf-8 -*-
+
+import sys

2022/day25.py

@@ -0,0 +1,3 @@
+# -*- encoding: utf-8 -*-
+
+import sys