Change default lint level to warning and deny warnings in CI (#397)

tests/test_buf.rs

@@ -1,4 +1,4 @@
-#![deny(warnings, rust_2018_idioms)]
+#![warn(rust_2018_idioms)]
 
 use bytes::Buf;
 #[cfg(feature = "std")]

tests/test_buf_mut.rs

@@ -1,4 +1,4 @@
-#![deny(warnings, rust_2018_idioms)]
+#![warn(rust_2018_idioms)]
 
 #[cfg(feature = "std")]
 use bytes::buf::IoSliceMut;

tests/test_bytes.rs

@@ -1,4 +1,4 @@
-#![deny(warnings, rust_2018_idioms)]
+#![warn(rust_2018_idioms)]
 
 use bytes::{Buf, BufMut, Bytes, BytesMut};
 

tests/test_chain.rs

@@ -1,4 +1,4 @@
-#![deny(warnings, rust_2018_idioms)]
+#![warn(rust_2018_idioms)]
 
 use bytes::buf::{BufExt, BufMutExt};
 use bytes::{Buf, BufMut, Bytes};

tests/test_debug.rs

@@ -1,4 +1,4 @@
-#![deny(warnings, rust_2018_idioms)]
+#![warn(rust_2018_idioms)]
 
 use bytes::Bytes;
 

tests/test_iter.rs

@@ -1,4 +1,4 @@
-#![deny(warnings, rust_2018_idioms)]
+#![warn(rust_2018_idioms)]
 
 use bytes::Bytes;
 

tests/test_reader.rs

@@ -1,4 +1,4 @@
-#![deny(warnings, rust_2018_idioms)]
+#![warn(rust_2018_idioms)]
 #![cfg(feature = "std")]
 
 use std::io::{BufRead, Read};

tests/test_serde.rs

@@ -1,5 +1,5 @@
 #![cfg(feature = "serde")]
-#![deny(warnings, rust_2018_idioms)]
+#![warn(rust_2018_idioms)]
 
 use serde_test::{assert_tokens, Token};
 

tests/test_take.rs

@@ -1,4 +1,4 @@
-#![deny(warnings, rust_2018_idioms)]
+#![warn(rust_2018_idioms)]
 
 use bytes::buf::{Buf, BufExt};