[ruby/io-console] Bump up 0.8.0

ruby/io-console@467508a0c6

Author: hsbt

ext/io/console/console.c

@@ -4,7 +4,7 @@
  */
 
 static const char *const
-IO_CONSOLE_VERSION = "0.8.0.beta1";
+IO_CONSOLE_VERSION = "0.8.0";
 
 #include "ruby.h"
 #include "ruby/io.h"