chore(ci): restrict token permissions (#7470)

Replace read-all with contents:read and add explicit permissions to
follow principle of least privilege.

Signed-off-by: Ville Vesilehto <ville@vesilehto.fi>

.github/workflows/release.yml

@@ -7,6 +7,9 @@ on:
         description: "Commit (e.g., 52f0348)"
         default: "master"
 
+permissions:
+  contents: read
+
 jobs:
   release:
     name: Release