chore: make rtnetlink versions explicit (firezone#3736)

If I do `rm Cargo.lock && cargo check --all` then I get errors about
rtnetlink.


![image](https://github.com/firezone/firezone/assets/13400041/c1eeff84-d65c-403d-9b33-24e00168ba36)

Dependabot tried to update these a couple weeks ago in firezone#3558 and it had
some conflicts, so I'm just making the old versions explicit so that
redoing the lockfile won't break anything.

This is because I got into a weird state with the new `dirs` dependency
for Linux where I removed it from Cargo.toml, but it was still in the
lockfile or something, so the program built even though it should not
have. And then when I tried to rebuild Cargo.lock I got these errors
about rtnetlink.

Author: ReactorScram

rust/Cargo.lock

@@ -31,7 +31,7 @@ futures-bounded = "0.2.1"
 domain = { version = "0.9", features = ["serde"] }
 dns-lookup = "2.0"
 tokio-tungstenite = "0.21"
-rtnetlink = { version = "0.14", default-features = false, features = ["tokio_socket"] }
+rtnetlink = { version = "0.14.1", default-features = false, features = ["tokio_socket"] }
 
 connlib-client-android = { path = "connlib/clients/android"}
 connlib-client-apple = { path = "connlib/clients/apple"}

rust/Cargo.toml

@@ -45,7 +45,7 @@ tempfile = "3.10.0"
 
 # Linux tunnel dependencies
 [target.'cfg(target_os = "linux")'.dependencies]
-netlink-packet-route = { version = "0.18", default-features = false }
+netlink-packet-route = { version = "0.19", default-features = false }
 netlink-packet-core = { version = "0.7", default-features = false }
 rtnetlink = { workspace = true }
 sd-notify = "0.4.1"