GitHub Workflows security hardening (#4761)

* build: harden integration_tests.yml permissions

Signed-off-by: Alex <aleksandrosansan@gmail.com>

* build: harden image_builds.yml permissions

Signed-off-by: Alex <aleksandrosansan@gmail.com>

Signed-off-by: Alex <aleksandrosansan@gmail.com>
Co-authored-by: Niklas Meyer <62480600+DerLinkman@users.noreply.github.com>

.github/workflows/image_builds.yml

@@ -5,6 +5,9 @@ on:
     branches: [ "master", "staging" ]
   workflow_dispatch:
 
+permissions:
+  contents: read # to fetch code (actions/checkout)
+
 jobs:
   docker_image_builds:
     strategy:

.github/workflows/integration_tests.yml

@@ -5,6 +5,9 @@ on:
     branches: [ "master", "staging" ]
   workflow_dispatch:
 
+permissions:
+  contents: read
+
 jobs:
   integration_tests:
     runs-on: ubuntu-latest