rbspy update (brings ruby 2.7.2 support)

Author: petethepig

third_party/rustdeps/Cargo.lock

@@ -10,4 +10,4 @@ crate-type = ["staticlib"]
 py-spy = { git = "https://github.com/pyroscope-io/py-spy", rev = "59f80f6" }
 
 [target.'cfg(target_arch = "x86_64")'.dependencies]
-rbspy = { git = "https://github.com/pyroscope-io/rbspy", rev = "00dbbe4" }
+rbspy = { git = "https://github.com/pyroscope-io/rbspy", rev = "6c4f67c" }