Extend tox setup to include core only testing

.gitlab-ci.yml

@@ -6,25 +6,45 @@ before_script:
 - python -V
 - pip install wheel tox
 
-test-3.5:
+test-3.5-core:
   image: python:3.5-buster
   script:  
-  - tox -e py35
+  - tox -e py35-core
 
-test-3.6:
+test-3.6-core:
   image: python:3.6-buster
   script:  
-  - tox -e py36
+  - tox -e py36-core
 
-test-3.7:
+test-3.7-core:
   image: python:3.7-buster
   script:  
-  - tox -e py37
+  - tox -e py37-core
 
-test-3.8:
+test-3.8-core:
   image: python:3.8-buster
   script:  
-  - tox -e py38
+  - tox -e py38-core
+
+test-3.5-all:
+  image: python:3.5-buster
+  script:  
+  - tox -e py35-all
+
+test-3.6-all:
+  image: python:3.6-buster
+  script:  
+  - tox -e py36-all
+
+test-3.7-all:
+  image: python:3.7-buster
+  script:  
+  - tox -e py37-all
+
+test-3.8-all:
+  image: python:3.8-buster
+  script:  
+  - tox -e py38-all
 
 deploy_production:
   stage: deploy