Merge pull request PowerDNS#13337 from Habbie/backport-12562-to-auth-…

…4.7.x

auth-4.7: fix github actions grub issue

build-scripts/gh-actions-setup-inv

@@ -6,6 +6,9 @@ EOF
 "
 sudo chmod 755 /usr/sbin/policy-rc.d
 sudo apt-get update
-sudo apt-get -qq -y --allow-downgrades dist-upgrade
+# FIXME: Avoid GRUB related errors due to runner image configuration by removing it.
+sudo dpkg --purge --force-all grub-efi-amd64-signed && sudo dpkg --purge --force-all shim-signed
+sudo apt-get autoremove
+sudo apt-get -qq -y dist-upgrade
 sudo apt-get -qq -y --no-install-recommends install python3-pip
 sudo pip3 install git+https://github.com/pyinvoke/invoke@faa5728a6f76199a3da1750ed952e7efee17c1da