ci(release): Add contents read for build-kwctl step call

Fixes invalid workflow error

Signed-off-by: Víctor Cuadrado Juan <vcuadradojuan@suse.de>

Author: viccuad

.github/workflows/release.yml

@@ -112,6 +112,7 @@ jobs:
     name: Build kwctl binaries
     uses: ./.github/workflows/build-kwctl.yml
     permissions:
+      contents: read
       id-token: write
       attestations: write
     with: