Fix mdbook ci & fix yUpdate always present in serialized commits

Author: Polleps

.dagger/src/index.ts

@@ -149,7 +149,7 @@ export class AtomicServer {
       .withMountedDirectory('/docs', actualDocsDirectory)
       .withWorkdir('/docs')
       .withExec(['mdbook', 'build'])
-      .directory('/docs/build/html');
+      .directory('/docs/build');
   }
 
   @func()

lib/src/commit.rs

@@ -504,11 +504,13 @@ impl Commit {
             );
         }
         if let Some(y_update) = &self.y_update {
-            let mut newy_update = PropVals::new();
-            for (prop, val) in y_update {
-                newy_update.insert(prop.into(), val.clone());
+            if !y_update.is_empty() {
+                let mut newy_update = PropVals::new();
+                for (prop, val) in y_update {
+                    newy_update.insert(prop.into(), val.clone());
+                }
+                resource.set_unsafe(urls::Y_UPDATE.into(), newy_update.into());
             }
-            resource.set_unsafe(urls::Y_UPDATE.into(), newy_update.into());
         }
         resource.set_unsafe(
             SIGNER.into(),