Fix install.sh script if curl is not present

[bashofmann]

At least with bash 5.0.18, GNU Wget 1.20.3 and GNU Awk 5.1.0 the wget installation methods fails because the awk regex does not match the location header. In these versions, instead of /^ Location:... it must be /^Location:.... In order to retain compatibility with other versions having a different behavior, I changed it to /^\s*Location:....

bash-5.0$ wget /~https://github.com/rancher/k3d/releases/latest --server-response -O /dev/null 2>&1 | awk '/^  Location: /{DEST=$2} END{ print DEST}'

bash-5.0$ wget /~https://github.com/rancher/k3d/releases/latest --server-response -O /dev/null 2>&1 | awk '/^Location: /{DEST=$2} END{ print DEST}'
/~https://github.com/rancher/k3d/releases/tag/v3.3.0

bash-5.0$ wget /~https://github.com/rancher/k3d/releases/latest --server-response -O /dev/null 2>&1 | awk '/^\s*Location: /{DEST=$2} END{ print DEST}'
/~https://github.com/rancher/k3d/releases/tag/v3.3.0

This also adds drone steps to test this script with both curl and wget.

[iwilltry42]

Thanks for this @bashofmann :)
I don't really understand, why this is happening, but the fix looks reasonable to me 👍
However, I wouldn't go with the extra drone steps, as they introduce unnecessary risks (network) that could prevent releases from being published.
I could imagine though putting them into GitHub Actions that run after a release has been published and then even check for the correct version being present (k3d version) after the installation 🤔

[bashofmann]

Sounds good, I removed the drone steps and will work an a Github Actions based test in a separate PR.

[iwilltry42]

Awesome, thank you!