chore: add bytes type (#308)

Co-authored-by: Luis Moreno <morenol@users.noreply.github.com>

Author: morenol

sdf/concepts/types.mdx

@@ -38,6 +38,26 @@ types:
 
 String is a sequence of characters.  It is defined as `string` type.
 
+```yaml
+types:
+  my-type:
+    type: string
+```
+
+<hr />
+
+## Bytes
+
+For raw binary data, we can use the `bytes` type. It is represented as a sequence of `u8`.
+
+Example:
+
+```yaml
+types:
+  raw-data:
+    type: bytes
+```
+
 <hr />
 
 ## Object