move coverage to pyproject.toml and exclude typechecking things (#7102)

Author: headtr1ck

.coveragerc

@@ -1,10 +1,22 @@
 [build-system]
+build-backend = "setuptools.build_meta"
 requires = [
-    "setuptools>=42",
-    "setuptools-scm[toml]>=3.4",
-    "setuptools-scm-git-archive",
+  "setuptools>=42",
+  "setuptools-scm[toml]>=3.4",
+  "setuptools-scm-git-archive",
 ]
-build-backend = "setuptools.build_meta"
 
 [tool.setuptools_scm]
 fallback_version = "999"
+
+[tool.coverage.run]
+exclude_lines = ["pragma: no cover", "if TYPE_CHECKING"]
+omit = [
+  "*/xarray/tests/*",
+  "*/xarray/core/dask_array_compat.py",
+  "*/xarray/core/npcompat.py",
+  "*/xarray/core/pdcompat.py",
+  "*/xarray/core/pycompat.py",
+  "*/xarray/core/types.py",
+]
+source = ["xarray"]