lnd: make ios fails

Background

Trying to build the framework for iOS with make ios.

Your environment

• lnd 0.v13.1-beta (building from master at commit 9331a259d8c132823a33f198ecc29c1af73ac7d1)
• Darwin Andreas-iMac-Pro.local 20.6.0 Darwin Kernel Version 20.6.0: Wed Jun 23 00:26:31 PDT 2021; root:xnu-7195.141.2~5/RELEASE_X86_64 x86_64
• go version go1.16.6 darwin/amd64 installed with homebrew.

Steps to reproduce

make ios is failing:

❯ make ios
 Re-creating vendor directory.
rm -r vendor/; GO111MODULE=on go mod vendor
rm: vendor/: No such file or directory
go: finding module for package go.opentelemetry.io/otel/semconv
github.com/lightningnetwork/lnd/cluster imports
	github.com/lightningnetwork/lnd/kvdb/etcd imports
	go.etcd.io/etcd/server/v3/embed imports
	go.opentelemetry.io/otel/semconv: package go.opentelemetry.io/otel/semconv provided by go.opentelemetry.io/otel at latest version v0.20.0 but not at required version v1.0.0-RC2
make: *** [vendor] Error 1