Add serde deny_unknown_fields to Config

This adds deny_unknown_fields to Config so that any typo mistakes
will be caught by the config validation.

src/config.rs

@@ -17,6 +17,7 @@ lazy_static::lazy_static! {
 
 #[derive(PartialEq, Eq, Debug, serde::Deserialize)]
 #[serde(rename_all = "kebab-case")]
+#[serde(deny_unknown_fields)]
 pub(crate) struct Config {
     pub(crate) relabel: Option<RelabelConfig>,
     pub(crate) assign: Option<AssignConfig>,
@@ -38,6 +39,7 @@ pub(crate) struct Config {
 }
 
 #[derive(PartialEq, Eq, Debug, serde::Deserialize)]
+#[serde(deny_unknown_fields)]
 pub(crate) struct NominateConfig {
     // team name -> label
     pub(crate) teams: HashMap<String, String>,
@@ -68,6 +70,7 @@ impl PingConfig {
 }
 
 #[derive(PartialEq, Eq, Debug, serde::Deserialize)]
+#[serde(deny_unknown_fields)]
 pub(crate) struct PingTeamConfig {
     pub(crate) message: String,
     #[serde(default)]
@@ -76,6 +79,7 @@ pub(crate) struct PingTeamConfig {
 }
 
 #[derive(PartialEq, Eq, Debug, serde::Deserialize)]
+#[serde(deny_unknown_fields)]
 pub(crate) struct AssignConfig {
     /// If `true`, then posts a warning comment if the PR is opened against a
     /// different branch than the default (usually master or main).
@@ -105,6 +109,7 @@ impl AssignConfig {
 }
 
 #[derive(PartialEq, Eq, Debug, serde::Deserialize)]
+#[serde(deny_unknown_fields)]
 pub(crate) struct NoMergesConfig {
     /// No action will be taken on PRs with these substrings in the title.
     #[serde(default)]
@@ -121,6 +126,7 @@ pub(crate) struct NoMergesConfig {
 }
 
 #[derive(PartialEq, Eq, Debug, serde::Deserialize)]
+#[serde(deny_unknown_fields)]
 pub(crate) struct NoteConfig {
     #[serde(default)]
     _empty: (),
@@ -133,6 +139,7 @@ pub(crate) struct MentionsConfig {
 }
 
 #[derive(PartialEq, Eq, Debug, serde::Deserialize)]
+#[serde(deny_unknown_fields)]
 pub(crate) struct MentionsPathConfig {
     pub(crate) message: Option<String>,
     #[serde(default)]
@@ -141,18 +148,21 @@ pub(crate) struct MentionsPathConfig {
 
 #[derive(PartialEq, Eq, Debug, serde::Deserialize)]
 #[serde(rename_all = "kebab-case")]
+#[serde(deny_unknown_fields)]
 pub(crate) struct RelabelConfig {
     #[serde(default)]
     pub(crate) allow_unauthenticated: Vec<String>,
 }
 
 #[derive(PartialEq, Eq, Debug, serde::Deserialize)]
+#[serde(deny_unknown_fields)]
 pub(crate) struct ShortcutConfig {
     #[serde(default)]
     _empty: (),
 }
 
 #[derive(PartialEq, Eq, Debug, serde::Deserialize)]
+#[serde(deny_unknown_fields)]
 pub(crate) struct PrioritizeConfig {
     pub(crate) label: String,
 }
@@ -176,6 +186,7 @@ impl AutolabelConfig {
 }
 
 #[derive(PartialEq, Eq, Debug, serde::Deserialize)]
+#[serde(deny_unknown_fields)]
 pub(crate) struct AutolabelLabelConfig {
     #[serde(default)]
     pub(crate) trigger_labels: Vec<String>,
@@ -196,6 +207,7 @@ pub(crate) struct NotifyZulipConfig {
 }
 
 #[derive(PartialEq, Eq, Debug, serde::Deserialize)]
+#[serde(deny_unknown_fields)]
 pub(crate) struct NotifyZulipLabelConfig {
     pub(crate) zulip_stream: u64,
     pub(crate) topic: String,
@@ -208,6 +220,7 @@ pub(crate) struct NotifyZulipLabelConfig {
 }
 
 #[derive(PartialEq, Eq, Debug, serde::Deserialize)]
+#[serde(deny_unknown_fields)]
 pub(crate) struct MajorChangeConfig {
     /// A username (typically a group, e.g. T-lang) to ping on Zulip for newly
     /// opened proposals.
@@ -243,18 +256,22 @@ impl MajorChangeConfig {
 }
 
 #[derive(PartialEq, Eq, Debug, serde::Deserialize)]
+#[serde(deny_unknown_fields)]
 pub(crate) struct GlacierConfig {}
 
 #[derive(PartialEq, Eq, Debug, serde::Deserialize)]
+#[serde(deny_unknown_fields)]
 pub(crate) struct CloseConfig {}
 
 #[derive(PartialEq, Eq, Debug, serde::Deserialize)]
+#[serde(deny_unknown_fields)]
 pub(crate) struct ReviewSubmittedConfig {
     pub(crate) review_labels: Vec<String>,
     pub(crate) reviewed_label: String,
 }
 
 #[derive(PartialEq, Eq, Debug, serde::Deserialize)]
+#[serde(deny_unknown_fields)]
 pub(crate) struct ReviewRequestedConfig {
     pub(crate) remove_labels: Vec<String>,
     pub(crate) add_labels: Vec<String>,
@@ -280,6 +297,7 @@ pub(crate) async fn get(
 
 #[derive(PartialEq, Eq, Debug, serde::Deserialize)]
 #[serde(rename_all = "kebab-case")]
+#[serde(deny_unknown_fields)]
 pub(crate) struct GitHubReleasesConfig {
     pub(crate) format: ChangelogFormat,
     pub(crate) project_name: String,