test: move itg exclusions to jest

Signed-off-by: CrazyMax <1951866+crazy-max@users.noreply.github.com>

__tests__/buildx/install.test.itg.ts

@@ -19,7 +19,9 @@ import * as fs from 'fs';
 
 import {Install} from '../../src/buildx/install';
 
-describe('download', () => {
+const maybe = !process.env.GITHUB_ACTIONS || (process.env.GITHUB_ACTIONS === 'true' && process.env.imageOS && process.env.imageOS.startsWith('ubuntu')) ? describe : describe.skip;
+
+maybe('download', () => {
   // prettier-ignore
   test.each(['latest'])(
     'install docker %s', async (version) => {