v4.4.21

v4.4.21

• support get intercept
  for example:

   use std::sync::Arc;
    use async_trait::async_trait;
    use rbatis::RBatis;
    use rbatis::intercept::{Intercept};

    #[derive(Debug)]
    pub struct MockIntercept {
    }
    #[async_trait]
    impl Intercept for MockIntercept {
    }
let mut rb = RBatis::new();
rb.set_intercepts(vec![Arc::new(MockIntercept{})]);
let intercept = rb.get_intercept::<MockIntercept>();