Remove Windows support

[genevieve]

Context

The v8go library currently supports binaries for mac, linux, and windows. The last release of this library with an updated version of v8 was in May. We have been making efforts to automate the upgrade process here so that we can ship releases more regularly as patches are released/CVEs are found and fixed. However, we've been unable to merge any of those upgrade PRs opened by the automation @GustavoCaso added because it fails to build the window binary on later versions of v8.

The windows binary is built using MinGW and relies on patches in a different repository to make the v8 binary compile. These patches have not been updated for later versions and so they fail to apply on upgrade attempts.

Additionally, there seems to be incompatibility with enabling Internationalization/ICU support with the existing windows build process because of what appears to be a reliance on something provided by VSCode.

As such:

1. We cannot ship releases of v8go because we cannot build the windows binary and do not want the versions of mac/linux to be out of step with windows. The last release with a v8 update is from May. We are 6 minors behind.
2. We cannot ship a release of v8go with ICU enabled in the v8 binary because we cannot build the windows binary with it using the current build process.

Proposal

This PR removes support for windows from v8go as a result of the above issues. If a user of the library can contribute a fix to the above issues now, great. We tried asking in the #v8go gophers channel a couple weeks ago but did not get much of a response. Until such time as a user is able to contribute the changes needed to make the windows binary build on recent versions of v8 & with intl support enabled, we can remove it as a blocker allowing us to cut releases of v8go with the latest v8 update for mac and linux, as well as with intl support.

[codecov]

Codecov Report

Merging #234 (eb46224) into master (a8a4920) will not change coverage.
The diff coverage is n/a.

@@ Coverage Diff @@ ## master #234 +/- ## ======================================= Coverage 95.87% 95.87% ======================================= Files 17 17 Lines 582 582 ======================================= Hits 558 558 Misses 15 15 Partials 9 9 

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[dylanahsmith]

Approving, but let's wait to hear from @rogchap

[epk]

Probably should also delete https://github.com/rogchap/v8go/tree/master/deps/windows_x86_64

[rogchap]

Makes sense to me; I've spent too many sleepless nights fighting to get Windows building right, with little success.

[dylanahsmith]

Tests on 1.16.8 windows-latest Expected — Waiting for status to be reported (Required)
Tests on 1.17.1 windows-latest Expected — Waiting for status to be reported (Required)

@rogchap looks like these will need to be removed from the required checks before merging.