fix(doctests): update prost (#750)

Author: lcian

sentry-tower/Cargo.toml

@@ -32,7 +32,7 @@ url = { version = "2.2.2", optional = true }
 
 [dev-dependencies]
 anyhow = "1"
-prost = "0.12.3"
+prost = "0.13.3"
 sentry = { path = "../sentry", default-features = false, features = ["test"] }
 sentry-anyhow = { path = "../sentry-anyhow" }
 tokio = { version = "1", features = ["macros", "rt-multi-thread"] }