Add directly rust to CI packages

.build.yml

@@ -1,16 +1,11 @@
 image: alpine/edge
 packages:
-    - curl
+    - rust
 
 sources:
   - https://git.sr.ht/~victormignot/yorokobot
 
 tasks: 
-  - setup: |
-      curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh
-      rustup toolchain install stable
-      rustup default stable
-  
   - format-check: |
       cd yorokobot
       cargo fmt --check