Merge branch 'ci-changes' into 'v0.9.9'

Fix submodule sync issues. #464

See merge request !234

.gitlab-ci.yml

@@ -120,6 +120,7 @@ install tests:
   image: python:3.7
   before_script:
     - git submodule sync
+    - sleep 5
     - git submodule update --init --jobs=4
   script:
     - pip install --upgrade pip
@@ -143,6 +144,7 @@ dev setup tests:
   stage: test
   image: python:3.7
   script:
+    - sleep 5
     - pip install --upgrade pip
     - ./setup.sh
     - python -m nomad.cli parse tests/data/parsers/vasp/vasp.xml

optimade-python-tools @ b5731ab6

-Subproject commit 11af5d0b67b53abf2d6593b40aa9b4a4735012e2
+Subproject commit b5731ab61f5ef0d019426523b8b21ad4c82596a2

example @ ca9596fc

-Subproject commit c378ce3c667fa0b6bd93ecdfd5699b7b9e165fa5
+Subproject commit ca9596fcf15f938122d55ae12222dede9e3610a0