rdkafka-sys: upgrade to librdkafka v1.4.2

Also allow rdkafka and rdkafka-sys to be versioned independently by
making rdkafka-sys follow SemVer. This will fix future scenarios like
the one described in issue fede1024#211.

changelog.md

@@ -1,5 +1,21 @@
 # Changelog
 
+See also the [rdkafka-sys changelog](rdkafka-sys/changelog.md).
+
+<a name="0.24.0"></a>
+## 0.24.0 (Unreleased)
+
+* Decouple versioning of rdkafka-sys from rdkafka. rdkafka-sys now has its
+  own [changelog](rdkafka-sys/changelog.md) and will follow SemVer conventions.
+  ([#211])
+
+[#211]: https://github.com/fede1024/rust-rdkafka/issues/211
+
+<a name="0.23.1"></a>
+## 0.23.1 (2020-01-13)
+
+* Fix build on docs.rs.
+
 <a name="0.23.0"></a>
 ## 0.23.0 (2019-12-31)
 

rdkafka-sys/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "rdkafka-sys"
-version = "1.3.1"
+version = "1.4.0+1.4.0"
 authors = ["Federico Giraud <[email protected]>"]
 build = "build.rs"
 links = "rdkafka"

rdkafka-sys/README.md

@@ -14,9 +14,12 @@ cargo install bindgen
 
 ## Version
 
-The rdkafka-sys version number is in the format `X.Y.Z-P`, where `X.Y.Z`
-corresponds to the librdkafka version, and `P` indicates the version of the
-rust bindings.
+The rdkafka-sys version number is in the format `X.Y.Z+RX.RY.RZ`, where `X.Y.Z`
+is the version of this crate and follows SemVer conventions, while `RX.RY.RZ`
+is the version of the bundled librdkafka.
+
+Note that versions before v1.4.0+1.4.0 did not follow this convention, and
+instead directly corresponded to the bundled librdkafka version.
 
 ## Build
 

rdkafka-sys/changelog.md

@@ -0,0 +1,8 @@
+# Changelog
+
+<a name="1.4.0+1.4.0"></a>
+## v1.4.0+1.4.0 (Unreleased)
+
+* Upgrade to librdkafka v1.4.0.
+
+* Start separate changelog for rdkafka-sys.