CI: fix publish-docs workflow

For some reason, even if we add ssh keys to known_hosts, it keeps
failing.
The failure is related to confirm prompt, that tries to open tty (that
is not available on CI).

Signed-off-by: Davide Bettio <davide@uninstall.it>

Author: bettio

.github/workflows/publish-docs.yaml

@@ -131,6 +131,7 @@ jobs:
         if: github.repository == 'atomvm/AtomVM'
         working-directory: /home/runner/work/AtomVM/AtomVM/www
         run: |
+          export GIT_SSH_COMMAND="ssh -o StrictHostKeyChecking=no"
           eval `ssh-agent -t 60 -s`
           echo "${{ secrets.PUBLISH_ACTION_KEY }}" | ssh-add -
           mkdir -p ~/.ssh/
@@ -139,4 +140,4 @@ jobs:
           echo "github.com ssh-rsa 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" >> ~/.ssh/known_hosts
           git remote add push_dest "git@github.com:atomvm/atomvm_www.git"
           git fetch push_dest
-          git diff --exit-code origin/Production || git push --set-upstream push_dest Production
+          git diff --exit-code push_dest/Production || git push --set-upstream push_dest Production