[GHA] fix several codecov issues (keras-team#912)

* [ci/cd] exclude keras_core/legacy from coverage.run|report,  add backend to codecov flags, move project config to pyproject.toml

* GHA codecov upload, fail ci if error

Author: kiukchung

pyproject.toml

@@ -17,3 +17,39 @@ known_first_party = ["keras_core", "tests"]
 default_section = "THIRDPARTY"
 line_length = 80
 extend_skip_glob=["examples/*", "guides/*"]
+
+[tool.pytest.ini_options]
+filterwarnings = [
+    "error",
+    "ignore::DeprecationWarning",
+    "ignore::ImportWarning",
+    "ignore::RuntimeWarning",
+    "ignore::PendingDeprecationWarning",
+    "ignore::FutureWarning",
+    "ignore::UserWarning",
+    # Ignore a spurious warning on tf-nightly related to save model changes.
+    "ignore:Custom mask layers require a config",
+]
+addopts = "-vv"
+
+# Do not run tests in the `build` folders
+norecursedirs = ["build"]
+
+[tool.coverage.report]
+exclude_lines = [
+    "pragma: no cover",
+    "@abstract",
+    "raise NotImplementedError",
+]
+omit = [
+    "*/*_test.py",
+    "keras_core/legacy/*",
+]
+
+[tool.coverage.run]
+branch = true
+omit = [
+    "*/*_test.py",
+    "keras_core/legacy/*",
+]
+

setup.cfg

@@ -1,34 +1,3 @@
-[tool:pytest]
-filterwarnings =
-    error
-    ignore::DeprecationWarning
-    ignore::ImportWarning
-    ignore::RuntimeWarning
-    ignore::PendingDeprecationWarning
-    ignore::FutureWarning
-    ignore::UserWarning
-    # Ignore a spurious warning on tf-nightly related to save model changes.
-    ignore:Custom mask layers require a config
-
-addopts=-vv
-
-# Do not run tests in the `build` folders
-norecursedirs = build
-
-[coverage:report]
-exclude_lines =
-    pragma: no cover
-    @abstract
-    raise NotImplementedError
-omit =
-    */*_test.py
-
-[coverage:run]
-omit =
-    */*_test.py
-
-branch = True
-
 [flake8]
 ignore =
     # Conflicts with black