* Updating the license from MPL to Business Source License
Going forward, this project will be licensed under the Business Source License v1.1. Please see our blog post for more details at https://hashi.co/bsl-blog, FAQ at https://hashi.co/license-faq, and details of the license at www.hashicorp.com/bsl.
* Update copyright file headers to BUSL-1.1
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Co-authored-by: hashicorp-copywrite[bot] <110428419+hashicorp-copywrite[bot]@users.noreply.github.com>
* removed packer.Cache and references since packer.Cache is never used except in the download step. The download step now uses the new func packer.CachePath(targetPath) for this, the behavior is the same.
* removed download code from packer that was reimplemented into the go-getter library: progress bar, http download restart, checksuming from file, skip already downloaded files, symlinking, make a download cancellable by context.
* on windows if packer is running without symlinking rights and we are getting a local file, the file will be copied instead to avoid errors.
* added unit tests for step_download that are now CI tested on windows, mac & linux.
* files are now downloaded under cache dir `sha1(filename + "?checksum=" + checksum) + file_extension`
* since the output dir is based on the source url and the checksum, when the checksum fails, the file is auto deleted.
* a download file is protected and locked by a file lock,
* updated docs
* updated go modules and vendors
