misc: Fix beta clippy issues

Fixing the following clippy issue using `cargo clippy --fix`:

error: variables can be used directly in the `format!` string
  --> build.rs:25:27
   |
25 |         version.push_str(&format!("-{}", extra_version));
   |                           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   |
   = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#uninlined_format_args

Signed-off-by: Bo Chen <bchen@crusoe.ai>

block/src/qcow/mod.rs

@@ -378,7 +378,7 @@ impl QcowHeader {
         }
 
         if let Some(backing_file_path) = self.backing_file_path.as_ref() {
-            write!(file, "{}", backing_file_path).map_err(Error::WritingHeader)?;
+            write!(file, "{backing_file_path}").map_err(Error::WritingHeader)?;
         }
 
         // Set the file length by seeking and writing a zero to the last byte. This avoids needing