add njalla-tlsa-rotate.py

Signed-off-by: Martin Matous <m@matous.dev>

README.md

@@ -84,6 +84,18 @@ Usage: `kernel-update.py`
 Alt.: `kernel-update.py <old-version> <new-version>`
 
 
+## njalla-tlsa-rotate.py
+Perform 3 1 1 + 3 1 1 TLSA key rollover for Maddy mailserver with 3h window. Since the script is stateless
+and rebooting a machine would interfere, reboot is blocked via logind for the duration.
+
+Status: active use
+
+Dependencies (python): certbot, cryptography, dasbus
+Dependencies (system): caddy, maddy, python3, systemd
+
+Usage: Invoke periodically using systemd timer.
+
+
 ---
 
 ## flac-convert.py