ci: simplify project dependencies for Python 3.6

Author: daniel-jones-dev

.gitlab-ci.yml

@@ -70,7 +70,6 @@ test:
     matrix:
       - DOCKER_IMAGE: "python:3.11"
       - DOCKER_IMAGE: "python:3.6"
-        EXTRA_POETRY_ADD_ARGUMENT: "pytest@6.2.3 coverage@5.5"
         USE_MOCK_SERVER: "use mock server"
       - DOCKER_IMAGE: "python:3.7"
         USE_MOCK_SERVER: "use mock server"
@@ -83,7 +82,7 @@ test:
       - DOCKER_IMAGE: "python:3.11"
         USE_MOCK_SERVER: "use mock server"
       - DOCKER_IMAGE: "python:3.6"
-        EXTRA_POETRY_ADD_ARGUMENT: "requests@2.0 pytest@6.2.3 coverage@5.5"
+        EXTRA_POETRY_ADD_ARGUMENT: "requests@2.0"
         USE_MOCK_SERVER: "use mock server"
       - DOCKER_IMAGE: "python:3.9"
         EXTRA_POETRY_ADD_ARGUMENT: "requests@2.0"

README.md

@@ -545,9 +545,6 @@ deepl-mock, run it in another terminal while executing the tests. Execute the
 tests using `pytest` with the `DEEPL_MOCK_SERVER_PORT` and `DEEPL_SERVER_URL`
 environment variables defined referring to the mock-server.
 
-Note: for testing on Python 3.6, you need to install an older version of
-`pytest` manually, using `poetry add pytest@6.2.3`. 
-
 [api-docs]: https://www.deepl.com/docs-api?utm_source=github&utm_medium=github-python-readme
 
 [api-docs-csv-format]: https://www.deepl.com/docs-api/managing-glossaries/supported-glossary-formats/?utm_source=github&utm_medium=github-python-readme

poetry.lock

@@ -45,9 +45,14 @@ black = "^21.4b2"
 pydantic = "^1.8.1"
 flake8 = "^3.9.2"
 # pytest v7.2.0 addresses a vulnerability but unfortunately only supports Python 3.7+
-# To test on Python 3.6 we install pytest v6.2.3 and coverage manually.
-pytest = { version = "^7.2.0", python = ">=3.7,<4" }
-coverage = {extras = ["toml"], version = "^6.5.0", python = ">=3.7,<4"}
+pytest = [
+    {version = "^7.2.0", python = ">=3.7,<4"},
+    {version = "^6.2.3", python = "<3.7"},
+]
+coverage = [
+    {extras = ["toml"], version = "^6.5.0", python = ">=3.7,<4"},
+    {extras = ["toml"], version = "^5.5.0", python = "<3.7"},
+]
 
 [tool.poetry.scripts]
 deepl = "deepl.__main__:main"