*: Prepare v0.19.0-alpha (#113)

Signed-off-by: Max Inden <mail@max-inden.de>

CHANGELOG.md

@@ -4,9 +4,64 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
-## [0.19.0] - unreleased
+## [0.19.0-alpha]
+
+This is a large release including multiple breaking changes. Major user-facing
+improvement of this release is support for the OpenMetrics Protobuf format.
+
+### Upgrade guide:
+
+- Don't box before registering.
+
+  ```diff
+    registry.register(
+        "my_metric",
+        "This is my metric",
+  -      Box::new(my_metric.clone()),
+  +      my_metric.clone(),
+    );
+  ```
+
+- Gauge uses `i64` instead of `u64`.
+
+  ```diff
+    my_gauge
+  -     .set(42u64);
+  +     .set(42i64);
+  ```
+
+- Derive `EncodeLabelSet` for `struct` and `EncodeLabelValue` for `enum` instead of just `Encode` for all and require `Debug`.
+
+  ```diff
+  - #[derive(Clone, Hash, PartialEq, Eq, Encode)]
+  + #[derive(Clone, Hash, PartialEq, Eq, EncodeLabelSet, Debug)]
+    struct Labels {
+        path: String,
+        method: Method,
+        some_number: u64,
+    }
+
+  - #[derive(Clone, Hash, PartialEq, Eq, Encode)]
+  + #[derive(Clone, Hash, PartialEq, Eq, EncodeLabelValue, Debug)]
+    enum Method {
+        Get,
+        #[allow(dead_code)]
+        Put,
+    }
+  ```
+
+- Encode as utf-8 and not as `[u8]`.
+
+  ```diff
+  - let mut buffer = vec![];
+  + let mut buffer = String::new();
+    encode(&mut buffer, &registry).unwrap();
+  ```
+
+For details on each of these, see changelog entries below.
 
 ### Added
+
 - Added support for the OpenMetrics protobuf format. See [PR 83].
 - Added a `remove` method to `Family` to allow the removal of a specified label
   set from a family. See [PR 85].

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "prometheus-client"
-version = "0.19.0"
+version = "0.19.0-alpha"
 authors = ["Max Inden <mail@max-inden.de>"]
 edition = "2021"
 description = "Open Metrics client library allowing users to natively instrument applications."
@@ -21,7 +21,7 @@ members = ["derive-encode"]
 dtoa = "1.0"
 itoa = "1.0"
 parking_lot = "0.12"
-prometheus-client-derive-encode = { version = "0.3.0", path = "derive-encode" }
+prometheus-client-derive-encode = { version = "0.4.0", path = "derive-encode" }
 prost = { version = "0.11.0", optional = true }
 prost-types = { version = "0.11.0", optional = true }
 

derive-encode/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "prometheus-client-derive-encode"
-version = "0.3.1"
+version = "0.4.0"
 authors = ["Max Inden <mail@max-inden.de>"]
 edition = "2021"
 description = "Auxiliary crate to derive Encode trait from prometheus-client."