chore(CODEOWNERS): add Engineering for workflows and CODEOWNERS (#394)

Author: caugner

.github/CODEOWNERS

@@ -0,0 +1,9 @@
+# ----------------------------------------------------------------------------
+# CODEOWNERS
+# ----------------------------------------------------------------------------
+# Order is important. The last matching pattern takes precedence.
+# See: https://docs.github.com/en/repositories/managing-your-repositorys-settings-and-features/customizing-your-repository/about-code-owners
+# ----------------------------------------------------------------------------
+
+/.github/workflows/ @mdn/engineering
+/.github/CODEOWNERS @mdn/engineering