ci: setup zizmor

Zizmor is a linter for GitHub Actions

.github/workflows/docs-preview.yaml

@@ -7,6 +7,8 @@ on:
       - 'scripts/build-docs.sh'
       - '.github/workflows/docs-preview.yaml'
 
+permissions: {}
+
 jobs:
   scripts:
     name: build 
@@ -16,6 +18,8 @@ jobs:
       url: https://staging.chatmail.at/doc/relay/${{ steps.prepare.outputs.prid }}
     steps:
       - uses: actions/checkout@v4
+        with:
+          persist-credentials: false
 
       - name: initenv 
         run: scripts/initenv.sh
@@ -34,18 +38,22 @@ jobs:
       - name: Get Pullrequest ID
         id: prepare
         run: |
-          export PULLREQUEST_ID=$(echo "${{ github.ref }}" | cut -d "/" -f3)
+          export PULLREQUEST_ID=$(echo "${GITHUB_REF}" | cut -d "/" -f3)
           echo "prid=$PULLREQUEST_ID" >> $GITHUB_OUTPUT
           if [ $(expr length "${{ secrets.USERNAME }}") -gt "1" ]; then echo "uploadtoserver=true" >> $GITHUB_OUTPUT; fi
       - run: |
-          echo "baseurl: /${{ steps.prepare.outputs.prid }}" >> _config.yml
+          echo "baseurl: /${STEPS_PREPARE_OUTPUTS_PRID}" >> _config.yml
+        env:
+          STEPS_PREPARE_OUTPUTS_PRID: ${{ steps.prepare.outputs.prid }}
 
       - name: Upload preview
         run: |
           mkdir -p "$HOME/.ssh"
           echo "${{ secrets.CHATMAIL_STAGING_SSHKEY }}" > "$HOME/.ssh/key"
           chmod 600 "$HOME/.ssh/key"
-          rsync -rILvh -e "ssh -i $HOME/.ssh/key -o StrictHostKeyChecking=no" $GITHUB_WORKSPACE/doc/build/ "${{ secrets.USERNAME }}@chatmail.at:/var/www/html/staging.chatmail.at/doc/relay/${{ steps.prepare.outputs.prid }}/"
+          rsync -rILvh -e "ssh -i $HOME/.ssh/key -o StrictHostKeyChecking=no" $GITHUB_WORKSPACE/doc/build/ "${{ secrets.USERNAME }}@chatmail.at:/var/www/html/staging.chatmail.at/doc/relay/${STEPS_PREPARE_OUTPUTS_PRID}/"
+        env:
+          STEPS_PREPARE_OUTPUTS_PRID: ${{ steps.prepare.outputs.prid }}
 
       - name: check links 
         working-directory: doc