refactor: auto generate electron_version.h from the version file (#18866)

* refactor: auto generate electron_version.h from the version file

* Update BUILD.gn

Co-Authored-By: Jeremy Apthorp <nornagon@nornagon.net>

script/generate-version-json.js

@@ -0,0 +1,28 @@
+const fs = require('fs')
+const path = require('path')
+const semver = require('semver')
+
+const outputPath = process.argv[2]
+
+const currentVersion = fs.readFileSync(path.resolve(__dirname, '../ELECTRON_VERSION'), 'utf8').trim()
+
+const parsed = semver.parse(currentVersion)
+
+let prerelease = ''
+if (parsed.prerelease && parsed.prerelease.length > 0) {
+  prerelease = parsed.prerelease.join('.')
+}
+
+const {
+  major,
+  minor,
+  patch
+} = parsed
+
+fs.writeFileSync(outputPath, JSON.stringify({
+  major,
+  minor,
+  patch,
+  prerelease,
+  has_prerelease: prerelease === '' ? 0 : 1
+}, null, 2))