Add read permissions to GitHub workflow files

This commit adds read permissions for 'contents' in the GitHub workflow files sonarqube.yml and reuse.yml. This allows these specific workflows to access the relevant contents they need for execution.

.github/workflows/reuse.yml

@@ -6,6 +6,9 @@ name: REUSE Compliance Check
 
 on: [push, pull_request]
 
+permissions:
+  contents: read
+
 jobs:
   test:
     runs-on: ubuntu-latest

.github/workflows/sonarqube.yml

@@ -3,6 +3,10 @@
 # SPDX-License-Identifier: CC0-1.0
 
 name: SonarQube
+
+permissions:
+  contents: read
+
 on:
   push:
     branches: