Add "changes" output variable to support matrix job configuration

action.yml

@@ -37,6 +37,9 @@ inputs:
       This option takes effect only when changes are detected using git against different base branch.
     required: false
     default: '10'
+outputs:
+  changes:
+    description: JSON array with names of all filters matching any of changed files
 runs:
   using: 'node12'
   main: 'dist/index.js'