github actions tests: initial (#4469)

* github actions tests: initial

* build: tests: add codecov action

tests/func/test_cache.py

@@ -1,4 +1,5 @@
 import os
+import platform
 import stat
 
 import configobj
@@ -163,6 +164,10 @@ class TestCmdCacheDir(TestDvc):
         config = configobj.ConfigObj(self.dvc.config.files["repo"])
         self.assertEqual(config["cache"]["dir"], dname.replace("\\", "/"))
 
+    @pytest.mark.skipif(
+        platform.system() == "Darwin",
+        reason="https://github.com/iterative/dvc/issues/4418",
+    )
     def test_relative_path(self):
         tmpdir = self.mkdtemp()
         dname = relpath(tmpdir)