Log Message:
*/*unit*: update NGINX Unit from 1.31.0 to 1.31.1

<ChangeLog>

*) Feature: allow to set the HTTP response status in Wasm module.

*) Feature: allow uploads larger than 4GiB in Wasm module.

*) Bugfix: application process could crash while rewriting URLs with
   query strings.

*) Bugfix: requests larger than about 64MiB could cause error in Wasm
   module.

*) Bugfix: when using many headers in Java module some of them could be
   corrupted due to memory realocation issue.

*) Bugfix: ServerRequest.destroy() implemented in Node.js module to make
   it compatible with some frameworks that might use it.

*) Bugfix: chunk argument of ServerResponse.write() can now be a
   Uint8Array to improve compatibility with Node.js 15.0.0 and above.

*) Bugfix: Node.JS unit-http NPM module now has appropriate default
   paths for macOS/arm64 systems.

*) Bugfix: build on musl libc with clang.

</ChangeLog>