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/boards/model/mocks/mockservicesapi.go

@@ -2,7 +2,7 @@
 // See LICENSE.txt for license information.
 
 // Code generated by MockGen. DO NOT EDIT.
-// Source: github.com/mattermost/mattermost-server/v6/server/boards/model (interfaces: ServicesAPI)
+// Source: github.com/mattermost/mattermost-server/server/v8/boards/model (interfaces: ServicesAPI)
 
 // Package mocks is a generated GoMock package.
 package mocks
@@ -13,8 +13,8 @@ import (
 
 	gomock "github.com/golang/mock/gomock"
 	mux "github.com/gorilla/mux"
-	model "github.com/mattermost/mattermost-server/v6/model"
-	mlog "github.com/mattermost/mattermost-server/v6/server/platform/shared/mlog"
+	model "github.com/mattermost/mattermost-server/server/v8/model"
+	mlog "github.com/mattermost/mattermost-server/server/v8/platform/shared/mlog"
 )
 
 // MockServicesAPI is a mock of ServicesAPI interface.

server/boards/model/mocks/propValueResolverMock.go

@@ -2,7 +2,7 @@
 // See LICENSE.txt for license information.
 
 // Code generated by MockGen. DO NOT EDIT.
-// Source: github.com/mattermost/mattermost-server/v6/server/boards/model (interfaces: PropValueResolver)
+// Source: github.com/mattermost/mattermost-server/server/v8/boards/model (interfaces: PropValueResolver)
 
 // Package mocks is a generated GoMock package.
 package mocks
@@ -11,7 +11,7 @@ import (
 	reflect "reflect"
 
 	gomock "github.com/golang/mock/gomock"
-	model "github.com/mattermost/mattermost-server/v6/server/boards/model"
+	model "github.com/mattermost/mattermost-server/server/v8/boards/model"
 )
 
 // MockPropValueResolver is a mock of PropValueResolver interface.