Improve publish action configuration

Author: zakcutner

.github/workflows/publish.yml

@@ -1,5 +1,7 @@
 name: Publish
-on: release
+on:
+  release:
+    types: [released]
 jobs:
   cargo:
     name: Cargo
@@ -9,6 +11,7 @@ jobs:
       - uses: actions-rs/toolchain@v1
         with:
           default: true
-      - env: CARGO_REGISTRY_TOKEN: ${{ secrets.CARGO_REGISTRY_TOKEN }}
+      - env:
+          CARGO_REGISTRY_TOKEN: ${{ secrets.CARGO_REGISTRY_TOKEN }}
         run: cargo login "$CARGO_REGISTRY_TOKEN"
       - run: cargo publish