chore: register new pytest ssh key mock markers in pyproject.toml

In PR #406, two pytest marks were added to help with mocking ssh
keys in unit tests, but the marks were not registered with pytest
so it was raising errors. This commit fixes that!

Also, migrate existing pytest configuration from tox.ini to
pyproject.toml

VERSION

@@ -1 +1 @@
-1!10.1.2
+1!10.2.0

pyproject.toml

@@ -52,3 +52,12 @@ extend-select = [
 
 [tool.ruff.lint.pydocstyle]
 convention = "pep257"
+
+[tool.pytest.ini_options]
+markers = [
+    "mock_ssh_keys: mock the base cloud _get_ssh_keys method to avoid checking for ssh keys",
+    "dont_mock_ssh_keys: if a class or method is marked with this, it will override the mock_ssh_keys marker",
+    "ci: run test as part of continuous integration on PRs using GitHub Actions",
+    "main_check: run test as part of continuous integration after branch has merged to main using GitHub Actions",
+]
+testpaths = ["tests/unit_tests"]

tox.ini

@@ -97,9 +97,3 @@ commands = {envpython} -m pytest -n 5 -m main_check --log-cli-level=DEBUG -svv {
 deps = {[testenv:integration-tests-ci]deps}
 passenv =
     GOOGLE_APPLICATION_CREDENTIALS
-
-[pytest]
-testpaths = tests/unit_tests
-markers =
-    ci: run test on as part of continuous integration
-    main_check: run test after branch has merged to main