Updating package zipping

[brettsam]

The DotNetZip nuget package is deprecated and we need to remove support for it. On top of that, we've had a gozip utility that we build and maintain and that ships alongside Core Tools for the express reason of zipping packages that are mountable in Linux using fuse-zip, which is what is used in production.

The goal here is to move the default zipping to use a new in-proc zip utility rather than maintaining the gozip build and deployment long term to make things simpler.

The reason for gozip in the first place was that Linux executable file permissions were not being correctly applied when the zip file was created in Windows when using System.IO.Compression.ZipArchive. This is because of some uniqueness in the way gozip creates these zips and the way fuse-zip mounts them:

• it's explicitly setting the file's mode to rwx (even on windows)
• when this happens in go, it auto-flips the "created by" byte in the zip entry header from "FAT" to "Unix"
• when unzipped, unzippers typically (although not always?) look at this header to know whether to honor the zip entry's mode. fuse-zip, the one we use to mount zips, looks at this to determine if it should care about the file's mode. If it's "FAT", it treats the modes as windows and sets it to 444 (unless it's explicitly read-only).
• the .Net zip lib doesn't do this -- or allow you access to that "created by" setting at all. It does let you set attributes... but the "created by" byte is always dependent on the OS you're zipping from.
• the library i pulled into the worker a while ago, SharpZibLib, does let you

However, rather than pull in yet another external dependency, I decided to use ZipArchive, but modify the resulting stream when running on Windows to flip each file to be marked as CreatedByUnix.

I've also added a full test that, when running on CI, takes a zip created on Windows and mounts it on Linux using fuse-zip to ensure that it is runnable.

As an escape-hatch, I'm leaving gozip as part of the build and using the setting of FUNCTIONS_CORE_TOOLS_USE_GOZIP the local environment will change the zipping mechanism back. I also added telemetry so we can see usage. Once we're confident, we can remove this entirely in a future release.

• My changes do not require documentation changes
  • Otherwise: Documentation issue linked to PR
• My changes do not need to be backported to a previous version
  • Otherwise: Backport tracked by issue/PR Updating package zipping #4264
• I have added all required tests (Unit tests, E2E tests)

[liliankasem]

lgtm, I like that you included a feature flag as a fail safe via the environment variable + included telemetry! Woild like to see more tests for macos as well

[aishwaryabh]

LGTM! Left some nit comments :)

[fabiocav]

Approving, but left some small comments.

[fabiocav]

Would also be good to add a note about this change to the release notes.