Add timeout

Don't want this action running forever if it is being ignored. Might be
nice to add a way to prevent the timeout from occurring if the user is
currently logged in.

script.sh

@@ -23,8 +23,10 @@ tmate -S /tmp/tmate.sock wait tmate-ready
 echo To connect to this session copy-n-paste the following into a terminal:
 tmate -S /tmp/tmate.sock display -p '#{tmate_ssh}'
 
-# Wait for connection to close
+# Wait for connection to close or timeout in 15 min
+timeout=$((15*60))
 while [ -S /tmp/tmate.sock ]; do
   sleep 1
+  timeout=$(($timeout-1))
+  [ $timeout -gt 0 ] || exit 1
 done
-