Release 2.3.0 with append_with_flags

Author: jonhoo

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "imap"
-version = "2.2.0"
+version = "2.3.0"
 authors = ["Matt McCoy <[email protected]>",
            "Jon Gjengset <[email protected]>"]
 documentation = "https://docs.rs/imap/"
@@ -38,7 +38,7 @@ lazy_static = "1.4"
 [dev-dependencies]
 lettre = "0.9"
 lettre_email = "0.9"
-rustls-connector = "0.11.0"
+rustls-connector = "0.12.0"
 
 [[example]]
 name = "basic"