.github: Update issue template
.github: Update issue template

- fix issue with linebreak
- introduce shorter URL

The short URL was created with:

curl https://git.io/ -i \
  -F "url=https://github.com/cilium/cilium-sysdump/releases/latest/download//cilium-sysdump.zip" \
  -F "code=cilium-sysdump-latest.zip"

Not the extra '/' in the path, that was added to enforce custom
URL, as the original URL was created with a random path by accident,
and GitHub doesn't allow multiple shortcuts for exactly the same URL.

Signed-off-by: Ilya Dmitrichenko <59b6733e47280dc0842a1e64fb2a9c742d686e46@gmail.com>

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