Removes vendoring and updates to Go 1.18

[codefromthecrypt]

This updates to Go 1.18 and removes the vendor directory.

Per Go's release policy, Go 1.14 has been unsupported for a while.

This also adds CI so that we know the project can be built.

see mosn/mosn#2145 (comment)
see https://go.dev/doc/devel/release#policy

[codefromthecrypt]

ps for vendoring, I simply ran go mod vendor which did all the modules, not just rcrowley. If you have other commands or want to push a commit to do something different, please do so. Just check that go build ./... works afterwards, or also change CI to whatever command is expected.

[taoyuanyuan]

we can delete the vendor directory to ignore it, and do not modify the version of protobuf that depended on by istio.

[codefromthecrypt]

ok good advice. I'll remove vendoring and switch the protobuf version back to the older patch. I'll add a note in go.mod that this must match Istio.

[codefromthecrypt]

@taoyuanyuan on protobuf and Istio... I can't find an istio version that uses v1.5.0. Do you still want me to lock that version, or should we go with 1.5.2 instead?

istio 1.10.0 was released last may and uses protobuf v1.5.1 https://github.com/istio/istio/blob/1.10.0/go.mod

• before that, istio used protobuf v1.4.3 not v1.5.0

istio 1.11.0 was released last august with protobuf v1.5.2 and this is still in use in latest istio

I'd like to document something about istio, but I want to make sure it is relevant. Advice?

[taoyuanyuan]

https://github.com/envoyproxy/go-control-plane/blob/v0.10.0/go.mod
https://github.com/mosn/mosn/blob/0e489a0c809b7e1bbb041d4682e8da045613dd6e/go.mod#L67
oh, I'm sorry, I see MOSN uses go-control-plane v0.10.0 depended protobuf 1.5.0, but not istio.
We can make minimal changes and do not modify this version.

[codefromthecrypt]

thanks I'll make the appropriate comment as it will help the next person. Cheers!

[codefromthecrypt]

ok @taoyuanyuan PTAL!

[taoyuanyuan]

LGTM