Update tests.yml to include permissions

Add permissions section to GitHub Actions workflow

Signed-off-by: nuno maduro <enunomaduro@gmail.com>

Author: nunomaduro

.github/workflows/tests.yml

@@ -2,6 +2,9 @@ name: Tests
 
 on: ['push', 'pull_request']
 
+permissions:
+  contents: read
+
 jobs:
   ci:
     runs-on: ${{ matrix.os }}