chore: prepare Tokio v1.20.4 release

Author: carllerche

README.md

@@ -56,7 +56,7 @@ Make sure you activated the full features of the tokio crate on Cargo.toml:
 
 ```toml
 [dependencies]
-tokio = { version = "1.20.3", features = ["full"] }
+tokio = { version = "1.20.4", features = ["full"] }
 ```
 Then, on your main.rs:
 

tokio/CHANGELOG.md

@@ -1,3 +1,13 @@
+# 1.20.4 (January 17, 2023)
+
+Forward ports 1.18.5 changes.
+
+### Fixed
+
+- io: fix unsoundness in `ReadHalf::unsplit` ([#5375])
+
+[#5375]: https://github.com/tokio-rs/tokio/pull/5375
+
 # 1.20.3 (January 3, 2022)
 
 This release forward ports changes from 1.18.4.

tokio/Cargo.toml

@@ -6,7 +6,7 @@ name = "tokio"
 #   - README.md
 # - Update CHANGELOG.md.
 # - Create "v1.0.x" git tag.
-version = "1.20.3"
+version = "1.20.4"
 edition = "2018"
 rust-version = "1.49"
 authors = ["Tokio Contributors <[email protected]>"]

tokio/README.md

@@ -56,7 +56,7 @@ Make sure you activated the full features of the tokio crate on Cargo.toml:
 
 ```toml
 [dependencies]
-tokio = { version = "1.20.3", features = ["full"] }
+tokio = { version = "1.20.4", features = ["full"] }
 ```
 Then, on your main.rs: