Update docker.yml

Fix node.js <20 deprecation

Resolves #13997

Author: mosfet80

.github/workflows/docker.yml

@@ -13,7 +13,7 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-    - uses: actions/checkout@v3
+    - uses: actions/checkout@v4
     - name: Build image
       run: cd reproducible-builds && docker build -t signal-android . && cd ..