build: use eslint flat config

.github/workflows/check-dist.yml

@@ -1,8 +1,8 @@
-# `dist/index.js` is a special file in Actions.
+# `dist/index.cjs` is a special file in Actions.
 # When you reference an action with `uses:` in a workflow,
-# `index.js` is the code that will run.
+# `index.cjs` is the code that will run.
 # For our project, we generate this file through a build process from other source files.
-# We need to make sure the checked-in `index.js` actually matches what we expect it to be.
+# We need to make sure the checked-in `index.cjs` actually matches what we expect it to be.
 name: Check dist/
 
 on:
@@ -47,7 +47,7 @@ jobs:
           fi
         id: diff
 
-      # If index.js was different than expected, upload the expected version as an artifact
+      # If index.cjs was different than expected, upload the expected version as an artifact
       - uses: actions/upload-artifact@v4
         if: ${{ failure() && steps.diff.conclusion == 'failure' }}
         with:

action.yml

@@ -5,7 +5,7 @@ branding:
   color: 'blue'
 runs:
   using: 'node20'
-  main: 'dist/index.js'
+  main: 'dist/index.cjs'
 inputs:
   token:
     required: true