fix: update golangci-lint install URL from master to main - #423

Summary

Update the golangci-lint installer URL in build/task.yml from master to main.

Why

The golangci-lint project renamed their default branch from master to main. The install script on the master branch is now stale and contains outdated checksums, causing CI pipelines to fail with:

hash_sha256_verify checksum for 'golangci-lint-2.12.2-linux-amd64.tar.gz' did not verify <expected> vs <got>

The golangci-lint team explicitly documented this in their v2.12.0 and v2.12.1 release notes:

Important: If you are using the install script from the master branch:
https://raw.githubusercontent.com/golangci/golangci-lint/master/install.sh
This branch is not used anymore, we are using main.

Change

- curl -sSfL https://raw.githubusercontent.com/golangci/golangci-lint/master/install.sh
+ curl -sSfL https://raw.githubusercontent.com/golangci/golangci-lint/main/install.sh