ci: Rename 'tests' jobs to 'unit_tests' (#465)

Except the one running the integration tests and generating the coverage
rename 'format' job to 'black'

.gitlab-ci.yml

@@ -48,7 +48,7 @@ build:
     paths:
       - ${PRE_COMMIT_HOME}
 
-format:
+black:
   extends:
     - .code_changes
     - .pre-commit
@@ -96,17 +96,17 @@ ruff:
     - poetry install
     - poetry run pytest tests/unit
 
-tests:3.8:
+unit_tests:3.8:
   extends: .tests
   variables:
     PYTHON_VERSION: "3.8"
 
-tests:3.9:
+unit_tests:3.9:
   extends: .tests
   variables:
     PYTHON_VERSION: "3.9"
 
-tests:3.10:
+unit_tests:3.10:
   extends: .tests
   variables:
     PYTHON_VERSION: "3.10"
@@ -127,7 +127,7 @@ tests:3.11:cov:
         coverage_format: cobertura
         path: coverage.xml
 
-tests:3.12:
+unit_tests:3.12:
   extends: .tests
   variables:
     PYTHON_VERSION: "3.12"