build: fix using parallell make

We don't support it, so make sure targets run serially.

Fixe: https://github.com/jitsi/jitsi-meet/issues/6647

Makefile

 clean:
 	rm -fr $(BUILD_DIR)
 
+.NOTPARALLEL:
 deploy: deploy-init deploy-appbundle deploy-rnnoise-binary deploy-lib-jitsi-meet deploy-libflac deploy-css deploy-local
 
 deploy-init:
 deploy-local:
 	([ ! -x deploy-local.sh ] || ./deploy-local.sh)
 
+.NOTPARALLEL:
 dev: deploy-init deploy-css deploy-rnnoise-binary deploy-lib-jitsi-meet deploy-libflac
 	$(WEBPACK_DEV_SERVER)