Disable debug info and enable thin LTO for release builds

See https://doc.rust-lang.org/cargo/reference/profiles.html#release for the
release profile's defaults and
https://doc.rust-lang.org/cargo/reference/profiles.html#lto for an explanation
of link time optimizations (LTO).

Cargo.toml

@@ -70,5 +70,4 @@ tempfile = "3.5.0"
 tokio-test = "0.4.2"
 
 [profile.release]
-debug = true
-split-debuginfo = "packed"
+lto = "thin"