Fixes the Polaris download URL

[piar1989]

This PR fixes #1199

Checklist

• I have signed the CLA
• I have updated/added any relevant documentation

Description

What's the goal of this PR?

The goal of this PR is to fix a bug in get_polaris.sh where the script fails to download the Polaris binary for recent releases due to a mismatch in the release asset naming convention.

What changes did you make?

I updated the POLARIS_URL construction inside get_polaris.sh. It now dynamically strips the "v" prefix from the $INPUT_VERSION variable using tr -d "v" specifically for the asset filename part of the URL, while keeping the full tag for the download path.

What alternative solution should we consider, if any?

None. This is the most straightforward and lightweight way to handle the version string adjustment directly inside the Bash script without adding external dependencies.

[vitorvezani]

Thanks for the contribution @piar1989, to be backwards compatible, I think we will need something like this

if [[ "$INPUT_VERSION" == v* ]]; then
  POLARIS_URL=https://github.com/FairwindsOps/polaris/releases/download/$INPUT_VERSION/polaris_$(echo -n $INPUT_VERSION | tr -d "v")_linux_amd64.tar.gz
else
  POLARIS_URL=https://github.com/FairwindsOps/polaris/releases/download/$INPUT_VERSION/polaris_linux_amd64.tar.gz
fi

So that if old patterns are used, we still resolve to correct URL, i.e.:

• https://github.com/FairwindsOps/polaris/releases/download/4.2.0/polaris_linux_amd64.tar.gz