Relax minimum rust version

Author: Marwes

src/idct.rs

@@ -139,7 +139,9 @@ fn dequantize_and_idct_block_8x8_inner<'a, I>(
         // to encode as 0..255 by adding 128, so we'll add that before the shift
         const X_SCALE: i32 = 65536 + (128 << 17);
 
-        let [s0, rest @ ..] = chunk;
+        // TODO When the minimum rust version supports it
+        // let [s0, rest @ ..] = chunk;
+        let (s0, rest) = chunk.split_first().unwrap();
         if *rest == [Wrapping(0); 7] {
             let dcterm = stbi_clamp((stbi_fsh(*s0) + Wrapping(X_SCALE)) >> 17);
             output_chunk[0] = dcterm;