versions: Allow newer Rust versions

Rust 1.47.0 which is the latest we note as tested in versions.yaml is now
getting fairly old - many current distros have newer versions (e.g.
Rust 1.54.0 in Fedora 34).  Bring this more up to date.

Note that this is only updating the 'newest-version', not the minimum
required version.

The new version changes the name of the 'clippy::unknown_clipp_lints'
option to simply 'unknown_lints' so we need to change that as well to avoid
warnings.

fixes #2633

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>

src/agent/src/watcher.rs

@@ -3,7 +3,7 @@
 // SPDX-License-Identifier: Apache-2.0
 //
 
-#![allow(clippy::unknown_clippy_lints)]
+#![allow(unknown_lints)]
 
 use std::collections::HashMap;
 use std::path::{Path, PathBuf};

src/agent/vsock-exporter/src/lib.rs

@@ -12,7 +12,7 @@
 // payload, which allows the forwarder to know how many bytes it must read to
 // consume the trace span. The payload is a serialised version of the trace span.
 
-#![allow(clippy::unknown_clippy_lints)]
+#![allow(unknown_lints)]
 
 use async_trait::async_trait;
 use byteorder::{ByteOrder, NetworkEndian};

versions.yaml

@@ -255,7 +255,7 @@ languages:
       description: |
         'newest-version' is the latest version known to work when
         building Kata
-      newest-version: "1.47.0"
+      newest-version: "1.54.0"
 
 specs:
   description: "Details of important specifications"