Use single action entrypoint (#128)

Use the same bundled action entrypoint for both the main and post
phases.

Author: j178

CONTRIBUTING.md

@@ -25,10 +25,8 @@ Bundle the action `dist/` entrypoints for GitHub Actions:
 npm run bundle
 ```
 
-That command produces:
-
-- `dist/index.cjs` for the main action
-- `dist/post/index.cjs` for the post-step cache save
+That command produces `dist/index.cjs`, which is used for both the main action and
+the post-step cache save.
 
 The generated `dist/` files must be committed, because GitHub Actions consumers run the checked-in `dist/` output directly.
 

action.yml

@@ -42,7 +42,7 @@ outputs:
 runs:
   using: node24
   main: dist/index.cjs
-  post: dist/post/index.cjs
+  post: dist/index.cjs
 branding:
   icon: git-commit
   color: orange