list termux as an untested platform in README.md

Author: Mause

README.md

@@ -115,6 +115,7 @@ Some operating systems are enabled, but not actively tested or supported:
 
 - macOS
 - FreeBSD / OpenBSD
+- Termux
 
 Theoretically every Unix based system should work, but they will not be actively tested.
 It is also required that somebody provides initial test results before the OS is enabled