chore: add CODEOWNERS file (#2177)

Author: crutchcorn

.github/CODEOWNERS

@@ -0,0 +1,6 @@
+.github/ @TanStack/tanstack-core
+.nx/ @TanStack/tanstack-core
+nx.json @TanStack/tanstack-core
+.changeset/config.json @TanStack/tanstack-core
+scripts/ @TanStack/tanstack-core
+.npmrc @TanStack/tanstack-core