Changed the schedule type to snake case to support continuous_stable

Summary: So we can use `ContinuousStable` as `continuous_stable`

Differential Revision: D52874640

fbshipit-source-id: 811aeabd09a71fab9f7830d845bcc5708ec860e0

td_util/src/schedules.rs

@@ -30,12 +30,17 @@ use serde::Serialize;
     Eq,
     Hash
 )]
-#[display(style = "lowercase")]
-#[serde(rename_all = "lowercase")]
+/// Use snake_case so we can use the continuous_stable schedule type
+#[display(style = "snake_case")]
+#[clap(rename_all = "snake_case")]
 pub enum ScheduleType {
     #[default]
+    #[serde(rename = "diff")]
     Diff,
+    #[serde(rename = "continuous")]
     Continuous,
+    #[serde(rename = "continuous_stable")]
     ContinuousStable,
+    #[serde(rename = "landcastle")]
     Landcastle, // Should this be just "land"?
 }