ci: build.yml perms (#246)

Potential fix for code scanning alert no. 1: Workflow does not contain permissions

Co-authored-by: Copilot Autofix powered by AI <62310815+github-advanced-security[bot]@users.noreply.github.com>

Author: caarlos0

.github/workflows/build.yml

@@ -11,6 +11,8 @@ on:
 jobs:
   build:
     runs-on: ubuntu-latest
+    permissions:
+      contents: read
     steps:
       - uses: actions/checkout@08c6903cd8c0fde910a37f88322edcfb5dd907a8 # v5.0.0
       - uses: actions/setup-go@44694675825211faa026b3c33043df3e48a5fa00 # v6.0.0