Release 2.1.0: Improve Linode Object Storage support

[mwikala]

What changed

Version 2.1.0 updates the plugin for current Craft filesystem conventions while keeping Craft 4 support in place.

• Added a Linode-aware S3 adapter that avoids object ACL calls Linode Object Storage does not support, while retaining Flysystem multipart uploads and MIME-type detection. Uploads, copies, and moves now rely on the bucket’s own access settings instead of attempting unsupported per-object ACL changes.
• Updated the filesystem implementation for current AWS SDK handler compatibility and removed an unused credential-refresh path.
• Refined the settings screen with clearer endpoint, bucket, credential, cache, and Content-Disposition guidance.
• Clarified the README with current install instructions, environment-variable setup, and the distinction between a bucket URL and the regional API endpoint.
• Updated Craft/Flysystem dependency ranges for maintained Craft 4 and Craft 5 releases.
• Fixed the legacy volume-to-filesystem migration to look up the plugin’s actual handle, while retaining the old lookup as a fallback.
• Finalized the 2.1.0 changelog.

Why

Linode Object Storage is S3-compatible but does not implement object ACL operations. The previous generic adapter path could turn normal Craft file actions into ACL requests that Linode rejects. This change keeps object access policy where Linode expects it: on the bucket.

For files with public URLs enabled, the bucket or the relevant prefix must still be publicly readable in Linode; that is what allows browser previews and public asset links to load.