Update heapless to v0.7.0 and use const generics

Author: MathiasKoch

Cargo.toml

@@ -20,4 +20,4 @@ categories = ["embedded", "hardware-support", "no-std", "network-programming"]
 [dependencies]
 nb = "1"
 no-std-net = "0.5"
-heapless = "^0.6.1"
+heapless = "^0.7"

src/dns.rs

@@ -1,4 +1,4 @@
-use heapless::{consts, String};
+use heapless::String;
 use no_std_net::IpAddr;
 
 /// This is the host address type to be returned by `gethostbyname`.
@@ -43,5 +43,5 @@ pub trait Dns {
 	/// 255 bytes [`rfc1035`]
 	///
 	/// [`rfc1035`]: https://tools.ietf.org/html/rfc1035
-	fn get_host_by_address(&self, addr: IpAddr) -> nb::Result<String<consts::U256>, Self::Error>;
+	fn get_host_by_address(&self, addr: IpAddr) -> nb::Result<String<256>, Self::Error>;
 }