Deprecate Info::encode

#418

src/common.rs

@@ -740,6 +740,7 @@ impl Info<'_> {
     ///
     /// Note that this does _not_ include the PNG signature, it starts with the IHDR chunk and then
     /// includes other chunks that were added to the header.
+    #[deprecated(note = "Use Encoder+Writer instead")]
     pub fn encode<W: Write>(&self, mut w: W) -> encoder::Result<()> {
         // Encode the IHDR chunk
         let mut data = [0; 13];

src/encoder.rs

@@ -590,6 +590,7 @@ impl<W: Write> Writer<W> {
         }
 
         self.w.write_all(&[137, 80, 78, 71, 13, 10, 26, 10])?; // PNG signature
+        #[allow(deprecated)]
         info.encode(&mut self.w)?;
 
         Ok(self)