Auto merge of rust-lang#3907 - RalfJung:perm, r=RalfJung

fix workflow permissions

Copied from rust-lang/docs.rs#2611

Author: bors

src/tools/miri/.github/workflows/ci.yml

@@ -13,7 +13,8 @@ on:
     - cron: '44 4 * * *' # At 4:44 UTC every day.
 
 permissions:
-  contents: write
+  contents: read
+  pull-requests: write
 
 defaults:
   run: