Fix workflow permissions

Author: kipcole9

.github/workflows/precompile.yml

@@ -6,6 +6,12 @@ on:
       - "v*"
   workflow_dispatch:
 
+# softprops/action-gh-release needs write access to create / update the
+# GitHub Release that hosts the precompiled NIF tarballs. The default
+# GITHUB_TOKEN is read-only on repos created with the modern default.
+permissions:
+  contents: write
+
 jobs:
   linux:
     runs-on: ubuntu-latest