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/plugin/checker/check_api.go

@@ -0,0 +1,50 @@
+// Copyright (c) 2015-present Mattermost, Inc. All Rights Reserved.
+// See LICENSE.txt for license information.
+
+package main
+
+import (
+	"fmt"
+	"go/ast"
+	"go/token"
+
+	"github.com/mattermost/mattermost-server/server/v8/plugin/checker/internal/asthelpers"
+	"github.com/mattermost/mattermost-server/server/v8/plugin/checker/internal/version"
+)
+
+func checkAPIVersionComments(pkgPath string) (result, error) {
+	pkg, err := asthelpers.GetPackage(pkgPath)
+	if err != nil {
+		return result{}, err
+	}
+
+	apiInterface, err := asthelpers.FindInterface("API", pkg.Syntax)
+	if err != nil {
+		return result{}, err
+	}
+
+	invalidMethods := findInvalidMethods(apiInterface.Methods.List)
+	return result{Errors: renderErrors(pkg.Fset, invalidMethods)}, nil
+}
+
+func findInvalidMethods(methods []*ast.Field) []*ast.Field {
+	var invalid []*ast.Field
+	for _, m := range methods {
+		if !hasValidMinimumVersionComment(m.Doc.Text()) {
+			invalid = append(invalid, m)
+		}
+	}
+	return invalid
+}
+
+func hasValidMinimumVersionComment(s string) bool {
+	return version.ExtractMinimumVersionFromComment(s) != ""
+}
+
+func renderErrors(fset *token.FileSet, methods []*ast.Field) []string {
+	var out []string
+	for _, m := range methods {
+		out = append(out, renderWithFilePosition(fset, m.Pos(), fmt.Sprintf("missing a minimum server version comment on method %s", m.Names[0].Name)))
+	}
+	return out
+}