coap-message: Bump to 0.1.1 to make payload_mut more usable

Using coap-message with coap-lite has shown its MutableWritableMessage's
limitations when used with dynamically allocated payloads; the new
added method fixes this.

Cargo.toml

@@ -16,7 +16,7 @@ edition = "2018"
 doctest = false
 
 [dependencies]
-coap-message = { version = "0.1.0", optional = true }
+coap-message = { version = "0.1.1", optional = true }
 
 [features]
 default = ["std"]

src/impl_coap_message.rs

@@ -104,6 +104,10 @@ impl MutableWritableMessage for Packet {
     fn payload_mut(&mut self) -> &mut [u8] {
         &mut self.payload
     }
+    fn payload_mut_with_len(&mut self, len: usize) -> &mut [u8] {
+        self.payload.resize(len, 0);
+        &mut self.payload
+    }
     fn truncate(&mut self, length: usize) {
         self.payload.truncate(length)
     }