feat(ci): use custom builder image

.woodpecker/build.yml

@@ -13,8 +13,9 @@ steps:
       # Binaries, even debug ones, should be statically compiled
       - '[ "$(readelf -d target/debug/rieterd | grep NEEDED | wc -l)" = 0 ]'
 
+    # Clippy also performs a full build, so putting it here saves the CI a
+    # lot of work
   clippy:
     image: 'git.rustybever.be/chewing_bever/rieter-builder:1.79-alpine3.19'
-      # Clippy also performs a full build, so putting it here saves the CI a
-      # lot of work
+    commands:
       - cargo clippy -- --no-deps -Dwarnings