[keygen] Use workspace version for `tempfile` (#31722)

use workspace version for `tempfile`

keygen/Cargo.toml

@@ -22,7 +22,7 @@ solana-version = { workspace = true }
 tiny-bip39 = { workspace = true }
 
 [dev-dependencies]
-tempfile = "3.5.0"
+tempfile = { workspace = true }
 
 [[bin]]
 name = "solana-keygen"