Update README

README.md

@@ -27,11 +27,6 @@ When you click the indicator, you will be prompted for passphrase to unlock the
 
 - Linux environment (It's not been tested on other platform)
 - GPG tool chain (`gpg`, `gpg-agent`, `gpg-connect-agent`) above 2.1
-- `expect` tool by Don Libes: [Links](https://core.tcl-lang.org/expect/index)
-  - You can get this tool on most Linux distribution.
-
-Current implementation require a pty between this extension and GPG tools to send passphrase,
-so we use `expect` to handle this. I wish I can remove this dependency in the future.
 
 ## Issues & Reviews