[git-plugin] changed -S to -s in gcs alias fix #6104

Signed-off-by: Raj <charanraj.tc@gmail.com>

plugins/git/git.plugin.zsh

@@ -81,7 +81,7 @@ compdef _git gcount
 alias gcp='git cherry-pick'
 alias gcpa='git cherry-pick --abort'
 alias gcpc='git cherry-pick --continue'
-alias gcs='git commit -S'
+alias gcs='git commit -s'
 
 alias gd='git diff'
 alias gdca='git diff --cached'