Ensure ~/.emacs.d/data/ exists when testing ‘oni-core’

If the directory doesn’t exist, ‘recentf-mode’ will try to save the recent file
list and fail because Emacs automatically asks if the directory should be
created. Since the test is running in a non-interactive environment, it’ll fail
to read the user’s answer.

.gitlab-ci.yml

@@ -265,6 +265,8 @@ integration-test-oni-core:
   image: registry.gitlab.com/ryuslash/emacs-config
   dependencies:
     - package
+  before_script:
+    - mkdir -p ~/.emacs.d/data/
   script: make integration-test-oni-core TEST_ARCHIVE=$(realpath bin/)
 
 integration-test-oni-cpp: