.builds: prepare for splitting out examples in separate repository

The example module is moving to git.sr.ht/~eliasnaur/gio-example.
We still need some main package for testing gogio, so update reference
to use the module path (gioui.org/example).

Signed-off-by: Elias Naur <mail@eliasnaur.com>

.builds/openbsd.yml

@@ -19,6 +19,3 @@ tasks:
  - test_cmd: |
      cd gio/cmd
      go test ./...
- - test_example: |
-     cd gio/example
-     go test ./...