Merge pull request #7441 from ethereum-optimism/inphi/rollop

makefile: Update submodules recursively

Makefile

@@ -23,7 +23,7 @@ submodules:
 	# CI will checkout submodules on its own (and fails on these commands)
 	if [ -z "$$GITHUB_ENV" ]; then \
 		git submodule init; \
-		git submodule update; \
+		git submodule update --recursive; \
 	fi
 .PHONY: submodules