fix: support powershell constrained language mode

[jeremyspiegel]

Fixes #6917

In environments where PowerShell is in Constrained Language Mode, [Convert]::ToBase64String and [System.Text.Encoding]::UTF8.GetBytes won't work.

We're currently converting the output of Get-AuthenticodeSignature -LiteralPath '${tempUpdateFile}' | ConvertTo-Json -Compress to base64 in powershell to get possibly non-ascii data, which would otherwise be output in the current ANSI code page. This workaround was added in #5071, FYI @orzFly @hezhuojie.

I first tried setting PowerShell's [console]::OutputEncoding, but that is also not allowed in Constrained Language Mode. So this fix is to run chcp 65001 > NUL before running powershell.exe. See PowerShell/PowerShell#7233 for more context on this issue.

In order to test that this works with non-ascii certificate subject names, I created a github release signed with a self-signed certificate with a subject name of CN=你好 at https://github.com/jeremyspiegel/electron-updater-powershell-test/releases/tag/v1.0.1. I then added the certificate to my Trusted Root Certificate Authorities and added the following test in test/src/updater/nsisUpdaterTest.ts:

test("github powershell", async () => {
  const updater = await createNsisUpdater("1.0.0")
  updater.updateConfigPath = await writeUpdateConfig<GithubOptions>({
    provider: "github",
    owner: "jeremyspiegel",
    repo: "electron-updater-powershell-test",
    publisherName: ["CN=你好"]
  })
  const updateCheckResult = await updater.checkForUpdates()
  const downloadResult = await updateCheckResult?.downloadPromise
  expect(downloadResult).not.toBeUndefined()
})

In order to test that this works in PowerShell Constrained Language Mode, I created a system environment variable __PSLockDownPolicy=4 and ran the above test.

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Latest commit: dbece13

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 1 package

Name	Type
electron-updater	Patch

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