tracing: prepare to release v0.1.31 (tokio-rs#1937)

# 0.1.31 (February 17th, 2022)

This release increases the minimum supported Rust version (MSRV) to
1.49.0. In addition, it fixes some relatively rare macro bugs.

### Added

- Added `tracing-forest` to the list of related crates ([tokio-rs#1935])

### Changed

- Updated minimum supported Rust version (MSRV) to 1.49.0 ([tokio-rs#1913])

### Fixed

- Fixed the `warn!` macro incorrectly generating an event with the
  `TRACE` level ([tokio-rs#1930])
- Fixed macro hygiene issues when used in a crate that defines its own
  `concat!` macro, for real this time ([tokio-rs#1918])

Thanks to @QnnOkabayashi, @nicolaasg, and @teohhanhui for contributing
to this release!

[tokio-rs#1935]: tokio-rs#1935
[tokio-rs#1913]: tokio-rs#1913
[tokio-rs#1930]: tokio-rs#1930
[tokio-rs#1918]: tokio-rs#1918

Author: hawkw

tracing/CHANGELOG.md

@@ -1,4 +1,32 @@
-# 0.1.30 (February 3rd, 2021)
+# 0.1.31 (February 17th, 2022)
+
+This release increases the minimum supported Rust version (MSRV) to 1.49.0. In
+addition, it fixes some relatively rare macro bugs.
+
+### Added
+
+- Added `tracing-forest` to the list of related crates ([#1935])
+
+### Changed
+
+- Updated minimum supported Rust version (MSRV) to 1.49.0 ([#1913])
+
+### Fixed
+
+- Fixed the `warn!` macro incorrectly generating an event with the `TRACE` level
+  ([#1930])
+- Fixed macro hygiene issues when used in a crate that defines its own `concat!`
+  macro, for real this time ([#1918])
+
+Thanks to @QnnOkabayashi, @nicolaasg, and @teohhanhui for contributing to this
+release!
+
+[#1935]: https://github.com/tokio-rs/tracing/pull/1935
+[#1913]: https://github.com/tokio-rs/tracing/pull/1913
+[#1930]: https://github.com/tokio-rs/tracing/pull/1930
+[#1918]: https://github.com/tokio-rs/tracing/pull/1918
+
+# 0.1.30 (February 3rd, 2022)
 
 This release adds *experimental* support for recording structured field
 values using the [`valuable`] crate. See [this blog post][post] for

tracing/README.md

@@ -250,7 +250,7 @@ my_future
 is as long as the future's.
 
 The second, and preferred, option is through the
-[`#[instrument]`](https://docs.rs/tracing/0.1.30/tracing/attr.instrument.html)
+[`#[instrument]`](https://docs.rs/tracing/0.1.31/tracing/attr.instrument.html)
 attribute:
 
 ```rust
@@ -297,7 +297,7 @@ span.in_scope(|| {
 // Dropping the span will close it, indicating that it has ended.
 ```
 
-The [`#[instrument]`](https://docs.rs/tracing/0.1.30/tracing/attr.instrument.html) attribute macro
+The [`#[instrument]`](https://docs.rs/tracing/0.1.31/tracing/attr.instrument.html) attribute macro
 can reduce some of this boilerplate:
 
 ```rust