Remove trailing nullbytes that make extension install fail.

Author: Joachim Rosskopf

.github/workflows/_extension_deploy.yml

@@ -109,7 +109,6 @@ jobs:
         shell: bash
         env:
           BUCKET_NAME: ${{ vars.DEPLOY_S3_BUCKET }}
-          DUCKDB_EXTENSION_SIGNING_PK: ${{ secrets.S3_DUCKDB_ORG_EXTENSION_SIGNING_PK }}
         run: |
           pwd
           python3 -m pip install pip awscli