ci: limit workflow token permissions

Author: phucnguyen1707

.github/workflows/ci.yml

@@ -5,6 +5,9 @@ on:
     branches: [main]
   pull_request:
 
+permissions:
+  contents: read
+
 jobs:
   build:
     runs-on: ubuntu-latest

.github/workflows/mobile.yml

@@ -37,6 +37,9 @@ on:
         type: boolean
         default: false
 
+permissions:
+  contents: read
+
 defaults:
   run:
     working-directory: apps/mobile