readme: Add example to install kubeseal on linux

[sebastian-philipp]

Would be great to also have an example how how to easily install the binary on linux, not just for mac.

I ended up with

curl -s https://api.github.com/repos/bitnami-labs/sealed-secrets/releases/latest | jq -r '.assets[] | select(.name | endswith("linux-amd64.tar.gz")) | .browser_download_url' | wget -qi -
tar -xvzf kubeseal-*-linux-amd64.tar.gz kubeseal
mkdir -p ~/.local/bin
mv ./kubeseal ~/.local/bin/kubeseal

Would be great to have something like this in the readme.

[alvneiayu]

hi @sebastian-philipp

First of all, thanks a lot for sharing your solution. We are already reviewing a PR including a possible solution here.

Thanks

Álvaro

[alemorcuq]

Solved in #913