Move to go modules

[chenrui333]

Fixes #1807

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[chenrui333]

Circle back on the PR.

[codecov-io]

Codecov Report

Merging #1821 into master will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master    #1821   +/-   ##
=======================================
  Coverage   24.59%   24.59%           
=======================================
  Files          98       98           
  Lines        5071     5071           
=======================================
  Hits         1247     1247           
  Misses       3684     3684           
  Partials      140      140

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[chenrui333]

Remove vendor folder in favor of go modules to manage the dependencies.

https://research.swtch.com/vgo-module

The End of Vendoring
Vendor directories serve two purposes. First, they specify by their contents the exact version of the dependencies to use during gobuild. Second, they ensure the availability of those dependencies, even if the original copies disappear. On the other hand, vendor directories are also difficult to manage and bloat the repositories in which they appear. With the go.mod file specifying the exact version of dependencies to use during vgo build, and with proxy servers for ensuring availability, vendor directories are now almost entirely redundant. They can, however, serve one final purpose: to enable a smooth transition to the new versioned world.

When building a module, vgo (and later go) will completely ignore vendored dependencies; those dependencies will also not be included in the module's zip file. To make it possible for authors to move to vgo and go.mod while still supporting users who haven't converted, the new vgo vendorcommand populates a module's vendor directory with the packages users need to reproduce the vgo-based build.

[davidmccormick]

Many thanks for this super useful contribution! 🙏