Remove working tree files for publication (#1421)

Avoids an error encountered during publishing where everything published
except for `wasm-tools` itself because Cargo was warning about a dirty
source tree.

.github/workflows/publish.yml

@@ -80,6 +80,7 @@ jobs:
         tag_name: v${{ steps.tag.outputs.version }}
 
     - run: |
+        rm -rf dist main.log
         rustc ci/publish.rs
         ./publish publish
       env: