add OpenBSD to the list of supported platforms

closes #103

Author: Cube707

README.md

@@ -114,7 +114,7 @@ This library actively supports these operating systems:
 Some operating systems are enabled, but not actively tested or supported:
 
 - macOS
-- FreeBSD
+- FreeBSD / OpenBSD
 
 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

readchar/__init__.py

@@ -8,7 +8,7 @@
 from ._config import config
 
 
-if platform.startswith(("linux", "darwin", "freebsd")):
+if platform.startswith(("linux", "darwin", "freebsd", "openbsd")):
     from . import _posix_key as key
     from ._posix_read import readchar, readkey
 elif platform in ("win32", "cygwin"):