Update deprecated imports

examples/asyncstd1_smtp_starttls.rs

@@ -1,6 +1,6 @@
 use lettre::{
     transport::smtp::authentication::Credentials, AsyncSmtpTransport, AsyncStd1Executor,
-    AsyncStd1Transport, Message,
+    AsyncTransport, Message,
 };
 
 #[async_std::main]

examples/asyncstd1_smtp_tls.rs

@@ -1,6 +1,6 @@
 use lettre::{
     transport::smtp::authentication::Credentials, AsyncSmtpTransport, AsyncStd1Executor,
-    AsyncStd1Transport, Message,
+    AsyncTransport, Message,
 };
 
 #[async_std::main]

examples/tokio02_smtp_starttls.rs

@@ -4,8 +4,8 @@
 use tokio02_crate as tokio;
 
 use lettre::{
-    transport::smtp::authentication::Credentials, AsyncSmtpTransport, Message, Tokio02Executor,
-    Tokio02Transport,
+    transport::smtp::authentication::Credentials, AsyncSmtpTransport, AsyncTransport, Message,
+    Tokio02Executor,
 };
 
 #[tokio::main]

examples/tokio02_smtp_tls.rs

@@ -4,8 +4,8 @@
 use tokio02_crate as tokio;
 
 use lettre::{
-    transport::smtp::authentication::Credentials, AsyncSmtpTransport, Message, Tokio02Executor,
-    Tokio02Transport,
+    transport::smtp::authentication::Credentials, AsyncSmtpTransport, AsyncTransport, Message,
+    Tokio02Executor,
 };
 
 #[tokio::main]

examples/tokio1_smtp_starttls.rs

@@ -4,8 +4,8 @@
 use tokio1_crate as tokio;
 
 use lettre::{
-    transport::smtp::authentication::Credentials, AsyncSmtpTransport, Message, Tokio1Executor,
-    Tokio1Transport,
+    transport::smtp::authentication::Credentials, AsyncSmtpTransport, AsyncTransport, Message,
+    Tokio1Executor,
 };
 
 #[tokio::main]

examples/tokio1_smtp_tls.rs

@@ -4,8 +4,8 @@
 use tokio1_crate as tokio;
 
 use lettre::{
-    transport::smtp::authentication::Credentials, AsyncSmtpTransport, Message, Tokio1Executor,
-    Tokio1Transport,
+    transport::smtp::authentication::Credentials, AsyncSmtpTransport, AsyncTransport, Message,
+    Tokio1Executor,
 };
 
 #[tokio::main]