CI: nightly broken

[daywalker90]

The nightly ci is currently broken:

Created /home/runner/work/plugins/plugins/lightning/contrib/msggen/msggen/schema.json from 2 files
cargo build --quiet --bin cln-grpc
make: cargo: No such file or directory
make: *** [plugins/Makefile:300: target/debug/cln-grpc] Error 127
Error: Process completed with exit code 2.

I've tried to debug this but couldn't find the problem.

It works locally and in the cln repo.

I believe it has something to do with the change in the plugins/Makefile adding MSGGEN_GEN_ALL:

ElementsProject/lightning@374db23#diff-7eba0837a02c2deea05123583489cc7941f60b687718194ad0b30077c3181c62R297

Definition:

MSGGEN_GEN_ALL = \
	contrib/msggen/msggen/schema.json

Not to be confused with MSGGEN_GENALL