Fix rouille to 3.4

3.5 requires a bump in MSRV (but fixes RUSTSEC-2021-0131, so we probably
should update soon anyway)

Signed-off-by: Jonathan Schwender <[email protected]>

Author: jschwe

Cargo.lock

@@ -88,7 +88,7 @@ zstd = "0.6"
 crossbeam-utils = { version = "0.8", optional = true }
 libmount = { version = "0.1.10", optional = true }
 nix = { version = "0.23.1", optional = true }
-rouille = { version = "3", optional = true, default-features = false, features = ["ssl"] }
+rouille = { version = "~3.4", optional = true, default-features = false, features = ["ssl"] }
 syslog = { version = "5", optional = true }
 void = { version = "1", optional = true }
 version-compare = { version = "0.1.0", optional = true }