fix: builds failing due to input desc examples being evaluated by github

this time by using the HTML entity for the dollar sign to display it, because escaping apparently doesn't work

action.yml

@@ -10,19 +10,19 @@ inputs:
     description: |
       The Sigstore/cosign secret used to sign the image.
 
-      Example: `\${{ secrets.SIGNING_SECRET }}`
+      Example: `${{ secrets.SIGNING_SECRET }}`
     required: true
   registry_token:
     description: | 
       The token used to sign into the container registry.
 
-      Example: `\${{ github.token }}`
+      Example: `${{ github.token }}`
     required: true
   pr_event_number:
     description: |
       The event number used to tag images pushed from pull requests.
 
-      Example: `\${{ github.event.number }}`
+      Example: `${{ github.event.number }}`
     required: true
   registry:
     description: |