upgrade minimal version of cfg-if to 1.6 to fix macro resolution (webrtc-rs#400)

This should fix the issue webrtc-rs#373
it works on master and works on webrtc-rs#376

Co-authored-by: Tipuch <[email protected]>

Author: Tipuch

util/src/vnet/nat.rs

@@ -299,8 +299,7 @@ impl NetworkAddressTranslator {
                     to.set_destination_addr(&format!("{dst_ip}:{dst_port}"))?;
                 } else {
                     return Err(Error::Other(format!(
-                        "drop {} as {:?}",
-                        from,
+                        "drop {from} as {:?}",
                         Error::ErrNoAssociatedLocalAddress
                     )));
                 }

webrtc/Cargo.toml

@@ -55,6 +55,9 @@ pem = { version = "1", optional = true }
 # https://github.com/est31/rcgen/pull/88
 # Version 0.3.14 requires Rust 1.59.0 which we don't currently support
 time = "~0.3.1"
+# fixes "error: cannot find macro `__cfg_if_items` in this scope"
+# https://github.com/rust-lang/packed_simd/commit/127a0fc233dbab880e33aeaccdd23e799a8b798b
+cfg-if = "0.1.6"
 
 [dev-dependencies]
 tokio-test = "0.4.0" # must match the min version of the `tokio` crate above