src: set GOWORK to "off" for macOS builds

Explicitly set GOWORK to "off" when building macOS from source to
ensure we do not pick up go.work files from host repositories where the
action is being run.

Updates #287

Signed-off-by: Mario Minardi <mario@tailscale.com>

Author: mpminardi

dist/index.js

@@ -696,6 +696,7 @@ async function installTailscaleMacOS(
         env: {
           ...process.env,
           TS_USE_TOOLCHAIN: "1",
+          GOWORK: "off",
         },
         logMode: config.logMode,
       },