Upgrade client-go and related to 1.15

[markmandel]

What type of PR is this?

Uncomment only one /kind <> line, hit enter to put that in a new line, and remove leading whitespace from that line:

/kind breaking
/kind bug
/kind cleanup
/kind documentation

/kind feature

/kind hotfix

What this PR does / Why we need it:

This upgrade client-go, apimachinery, apiextensions-apiserver and related to support Kubernetes 1.15, as well as regenerated clients for our CRDs.

Also included is a fix to gen-crd-client.sh such that it can now use Go modules, as otherwise it was failing to generate clients.

Which issue(s) this PR fixes:

Work on #1478

Special notes for your reviewer:

The only edited files that are probably worth looking at are Dockerfile, gen-crd-client.sh and go.mod.
Everything else is generated / vendoring.

[agones-bot]

Build Failed 😱

Build Id: 2142dc6f-3237-4fe9-9ecf-dcd2a683e70f

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[markmandel]

panic: runtime error: invalid memory address or nil pointer dereference [recovered]
	panic: runtime error: invalid memory address or nil pointer dereference
[signal SIGSEGV: segmentation violation code=0x1 addr=0x0 pc=0x19faac0]

goroutine 1218 [running]:
testing.tRunner.func1(0xc0005d2100)
	/usr/local/go/src/testing/testing.go:874 +0x69f
panic(0x1bc19e0, 0x2b21820)
	/usr/local/go/src/runtime/panic.go:679 +0x1b2
agones.dev/agones/pkg/gameservers.(*Controller).createGameServerPod(0xc0003025a0, 0xc001187b00, 0x1d61b72, 0x8, 0xc000806000)
	/go/src/agones.dev/agones/pkg/gameservers/controller.go:596 +0x1220
agones.dev/agones/pkg/gameservers.(*Controller).syncGameServerCreatingState(0xc0003025a0, 0xc001187b00, 0xc0002bd130, 0xc0000ef080, 0xc0000eefd0)
	/go/src/agones.dev/agones/pkg/gameservers/controller.go:494 +0x5e9
agones.dev/agones/pkg/gameservers.TestControllerSyncGameServerCreatingState.func3(0xc0005d2100)
	/go/src/agones.dev/agones/pkg/gameservers/controller_test.go:675 +0x980
testing.tRunner(0xc0005d2100, 0xc0003d4fd0)
	/usr/local/go/src/testing/testing.go:909 +0x19a
created by testing.(*T).Run
	/usr/local/go/src/testing/testing.go:960 +0x652
FAIL	agones.dev/agones/pkg/gameservers	5.381s
ok  	agones.dev/agones/pkg/gameserversets	3.218s

Putting this here so it's easier to lookup, and find out what the culprit is when I dig into this.

[agones-bot]

Build Failed 😱

Build Id: dc31a90d-e431-4f87-b51c-442aa781759a

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[agones-bot]

Build Failed 😱

Build Id: 2149e122-18db-4434-9ddb-f902036b16d3

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[roberthbailey]

I'm not sure where these comments came from (did we add them by hand) but they are now out of date.

[markmandel]

go.mod is generated by the go tooling. I've bo idea where they came from.

I'll edit them by hand.

[markmandel]

Done!

[google-oss-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: markmandel, roberthbailey

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• OWNERS [markmandel,roberthbailey]

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[agones-bot]

Build Succeeded 👏

Build Id: 538a88c3-ba68-4203-a0ca-55ac0ca9078f

The following development artifacts have been built, and will exist for the next 30 days:

• image: gcr.io/agones-images/agones-controller:1.6.0-f3aa669
• image: gcr.io/agones-images/agones-sdk:1.6.0-f3aa669
• image: gcr.io/agones-images/agones-ping:1.6.0-f3aa669
• Linux C++ SDK (build): agonessdk-1.6.0-f3aa669-linux-arch_64.tar.gz
• SDK Server: agonessdk-server-1.6.0-f3aa669.zip

A preview of the website (the last 30 builds are retained):

• https://f3aa669-dot-preview-dot-agones-images.appspot.com/

To install this version:

• git fetch https://github.com/GoogleCloudPlatform/agones.git pull/1532/head:pr_1532 && git checkout pr_1532
• helm install ./install/helm/agones --namespace agones-system --name agones --set agones.image.tag=1.6.0-f3aa669