Fix gnutar check on windows

src/internal/cacheUtils.ts

@@ -117,8 +117,9 @@ export function getCacheFileName(compressionMethod: CompressionMethod): string {
 }
 
 export async function isGnuTarInstalled(): Promise<boolean> {
+  const gnuTar = `${process.env['windir']}\\Program Files\\Git\\usr\\bin\\tar.exe`
   const versionOutput = await getVersion('tar')
-  return versionOutput.toLowerCase().includes('gnu tar')
+  return versionOutput.toLowerCase().includes('gnu tar') || fs.existsSync(gnuTar)
 }
 
 export function assertDefined<T>(name: string, value?: T): T {