software: fix link to lttrs

software/software.mdown

@@ -7,7 +7,7 @@
 * **[Group-Office](https://github.com/Intermesh/groupoffice)** (Javascript): Open source groupware and collaboration platform
 * **[JMAP Demo Webmail](https://github.com/jmapio/jmap-demo-webmail)** (JavaScript, MIT): a sophisticated demo webmail client to be used as a base for new projects. Default client for the [proxy](https://proxy.jmap.io).
 * **[JMAP::Tester](https://metacpan.org/pod/JMAP::Tester)** (Perl, Perl5): a JMAP client made for testing JMAP servers.
-* **[Ltt.rs](https://github.com/iNPUTmice/lttrs-android)** (Java, Apache): an email client for Android
+* **[Ltt.rs](https://codeberg.org/iNPUTmice/lttrs-android)** (Java, Apache): an email client for Android
 * **[Mailtemi](https://mailtemi.com)** , a native iOS email client
 * **[meli](https://meli.delivery)** (Rust): terminal email client (GPLv3)
 * **[mujmap](https://github.com/elizagamedev/mujmap)** (Rust): Synchronize JMAP mail with [notmuch](https://notmuchmail.org)