Update `itertools`

Update to 0.10.1
diff --git a/Cargo.lock b/Cargo.lock
index 8ca6f26..e21e9d0 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -344,7 +344,7 @@
  "humantime 2.0.1",
  "ignore",
  "im-rc",
- "itertools 0.10.1",
+ "itertools",
  "jobserver",
  "lazy_static",
  "lazycell",
@@ -449,7 +449,7 @@
  "flate2",
  "git2",
  "glob",
- "itertools 0.10.1",
+ "itertools",
  "lazy_static",
  "remove_dir_all",
  "serde_json",
@@ -567,7 +567,7 @@
  "chalk-ir",
  "ena",
  "indexmap",
- "itertools 0.10.1",
+ "itertools",
  "petgraph",
  "rustc-hash",
  "tracing",
@@ -631,7 +631,7 @@
  "filetime",
  "futures 0.3.19",
  "if_chain",
- "itertools 0.10.1",
+ "itertools",
  "num_cpus",
  "parking_lot",
  "quote",
@@ -654,7 +654,7 @@
  "cargo_metadata",
  "clap 2.34.0",
  "indoc",
- "itertools 0.10.1",
+ "itertools",
  "opener",
  "regex",
  "shell-escape",
@@ -668,7 +668,7 @@
  "cargo_metadata",
  "clippy_utils",
  "if_chain",
- "itertools 0.10.1",
+ "itertools",
  "pulldown-cmark",
  "quine-mc_cluskey",
  "regex-syntax",
@@ -1792,15 +1792,6 @@
 
 [[package]]
 name = "itertools"
-version = "0.9.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "284f18f85651fe11e8a991b2adb42cb078325c996ed026d994719efcfca1d54b"
-dependencies = [
- "either",
-]
-
-[[package]]
-name = "itertools"
 version = "0.10.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "69ddb889f9d0d08a67338271fa9b62996bc788c7796a5c18cf057420aaed5eaf"
@@ -3145,7 +3136,7 @@
  "futures 0.3.19",
  "heck",
  "home",
- "itertools 0.10.1",
+ "itertools",
  "jsonrpc-core",
  "lazy_static",
  "log",
@@ -3187,7 +3178,7 @@
  "derive-new",
  "env_logger 0.9.0",
  "fst",
- "itertools 0.10.1",
+ "itertools",
  "json",
  "lazy_static",
  "log",
@@ -3418,7 +3409,7 @@
 name = "rustc_ast_passes"
 version = "0.0.0"
 dependencies = [
- "itertools 0.10.1",
+ "itertools",
  "rustc_ast",
  "rustc_ast_pretty",
  "rustc_attr",
@@ -3461,7 +3452,7 @@
 version = "0.0.0"
 dependencies = [
  "either",
- "itertools 0.10.1",
+ "itertools",
  "polonius-engine",
  "rustc_const_eval",
  "rustc_data_structures",
@@ -3543,7 +3534,7 @@
 dependencies = [
  "bitflags",
  "cc",
- "itertools 0.10.1",
+ "itertools",
  "jobserver",
  "libc",
  "object 0.28.1",
@@ -4027,7 +4018,7 @@
 version = "0.0.0"
 dependencies = [
  "coverage_test_macros",
- "itertools 0.10.1",
+ "itertools",
  "rustc_ast",
  "rustc_attr",
  "rustc_const_eval",
@@ -4428,7 +4419,7 @@
  "askama",
  "atty",
  "expect-test",
- "itertools 0.10.1",
+ "itertools",
  "minifier",
  "pulldown-cmark",
  "rayon",
@@ -4510,7 +4501,7 @@
  "env_logger 0.8.4",
  "getopts",
  "ignore",
- "itertools 0.9.0",
+ "itertools",
  "lazy_static",
  "log",
  "regex",
@@ -5190,7 +5181,7 @@
 dependencies = [
  "combine",
  "indexmap",
- "itertools 0.10.1",
+ "itertools",
  "kstring",
  "serde",
 ]