Update itertools from 0.7 to 0.13 (#522)

Author: waywardmonkeys

Cargo.toml

@@ -36,7 +36,7 @@ bincode = "1.3.1"
 indexmap = "2.1"
 rand="0.4"
 byteorder="1"
-itertools="^0.7"
+itertools="^0.13"
 serde_json = "1.0"
 graph_map = "0.1"
 

tests/import.rs

@@ -28,7 +28,7 @@ fn run_test<T>(test: T, expected: Vec<(usize, Vec<((u64, i64), i64)>)>) -> ()
     let out =
     results
         .into_iter()
-        .group_by(|&(_, t, _)| t)
+        .chunk_by(|&(_, t, _)| t)
         .into_iter()
         .map(|(t, vals)| {
             let mut vec = vals.map(|(v, _, w)| (v, w)).collect::<Vec<_>>();