fixup scanner/contributors

Signed-off-by: Frédéric BIDON <fredbi@yahoo.com>

Author: fredbi

.github/workflows/contributors.yml

@@ -63,7 +63,7 @@ jobs:
         assignees: fredbi
         reviewers: fredbi
         sign-commits: true
-        signoff: false
+        signoff: true # DCO
 
   auto-merge:
     # description: |

.github/workflows/scanner.yml

@@ -3,7 +3,10 @@ name: Vulnerability scans
 on:
   workflow_call:
 
-permissions: read-all
+  workflow_dispatch:
+
+permissions:
+  contents: read
 
 # description: |
 #   A fast vulnerability scan on the repo that effectively supplements ossf scorecard and codesql