Update itertools from 0.10 to 0.12

Author: dtolnay

tools/agenda-generator/Cargo.toml

@@ -9,6 +9,6 @@ chrono = { version = "0.4", features = ["serde"] }
 reqwest = { version = "0.11", features = ["blocking", "json"] }
 serde = { version = "1.0", features = ["derive"] }
 serde_json = "1.0"
-itertools = "0.10.1"
+itertools = "0.12"
 structopt = "0.3.21"
 color-eyre = "0.5.11"