v8.0 module release (#22975)

https://mattermost.atlassian.net/browse/MM-52079

```release-note
We upgrade the module version to 8.0. The new module path is github.com/mattermost-server/server/v8.
```


Co-authored-by: Doug Lauder <wiggin77@warpmail.net>

server/model/shared_channel_test.go

@@ -0,0 +1,66 @@
+// Copyright (c) 2015-present Mattermost, Inc. All Rights Reserved.
+// See LICENSE.txt for license information.
+
+package model
+
+import (
+	"strings"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func TestSharedChannelIsValid(t *testing.T) {
+	id := NewId()
+	now := GetMillis()
+	data := []struct {
+		name  string
+		sc    *SharedChannel
+		valid bool
+	}{
+		{name: "Zero value", sc: &SharedChannel{}, valid: false},
+		{name: "Missing team_id", sc: &SharedChannel{ChannelId: id}, valid: false},
+		{name: "Missing create_at", sc: &SharedChannel{ChannelId: id, TeamId: id}, valid: false},
+		{name: "Missing update_at", sc: &SharedChannel{ChannelId: id, TeamId: id, CreateAt: now}, valid: false},
+		{name: "Missing share_name", sc: &SharedChannel{ChannelId: id, TeamId: id, CreateAt: now, UpdateAt: now}, valid: false},
+		{name: "Invalid share_name", sc: &SharedChannel{ChannelId: id, TeamId: id, CreateAt: now, UpdateAt: now,
+			ShareName: "@test@"}, valid: false},
+		{name: "Too long share_name", sc: &SharedChannel{ChannelId: id, TeamId: id, CreateAt: now, UpdateAt: now,
+			ShareName: strings.Repeat("01234567890", 100)}, valid: false},
+		{name: "Missing creator_id", sc: &SharedChannel{ChannelId: id, TeamId: id, CreateAt: now, UpdateAt: now,
+			ShareName: "test"}, valid: false},
+		{name: "Missing remote_id", sc: &SharedChannel{ChannelId: id, TeamId: id, CreateAt: now, UpdateAt: now,
+			ShareName: "test", CreatorId: id}, valid: false},
+		{name: "Valid shared channel", sc: &SharedChannel{ChannelId: id, TeamId: id, CreateAt: now, UpdateAt: now,
+			ShareName: "test", CreatorId: id, RemoteId: id}, valid: true},
+	}
+
+	for _, item := range data {
+		appErr := item.sc.IsValid()
+		if item.valid {
+			assert.Nil(t, appErr, item.name)
+		} else {
+			assert.NotNil(t, appErr, item.name)
+		}
+	}
+}
+
+func TestSharedChannelPreSave(t *testing.T) {
+	now := GetMillis()
+
+	o := SharedChannel{ChannelId: NewId(), ShareName: "test"}
+	o.PreSave()
+
+	require.GreaterOrEqual(t, o.CreateAt, now)
+	require.GreaterOrEqual(t, o.UpdateAt, now)
+}
+
+func TestSharedChannelPreUpdate(t *testing.T) {
+	now := GetMillis()
+
+	o := SharedChannel{ChannelId: NewId(), ShareName: "test"}
+	o.PreUpdate()
+
+	require.GreaterOrEqual(t, o.UpdateAt, now)
+}