docs: Fix warning from sphinx
docs: Fix warning from sphinx

Sphinx complains:
  /srv/Documentation/install/upgrade.rst:298: WARNING: Bullet list ends without a blank line; unexpected unindent.
  /srv/Documentation/install/upgrade.rst:298: WARNING: Inline literal start-string without end-string.
  /srv/Documentation/install/upgrade.rst:298: WARNING: Inline literal start-string without end-string.

Signed-off-by: Joe Stringer <16a9a54ddf4259952e3c118c763138e83693d7fd@cilium.io>

tgraf/cilium,cilium-team/cilium,michi-covalent/cilium,cilium/cilium,cilium/cilium,michi-covalent/cilium,tgraf/cilium,cilium-team/cilium,tklauser/cilium,michi-covalent/cilium,michi-covalent/cilium,tklauser/cilium,cilium/cilium,tgraf/cilium,cilium/cilium,tgraf/cilium,tgraf/cilium,michi-covalent/cilium,tklauser/cilium,cilium/cilium,tgraf/cilium,tklauser/cilium,tklauser/cilium