[MM-17889] Implement validation of plugin API version comments (#11941)

plugin/checker/test/invalid/invalid.go

@@ -0,0 +1,16 @@
+// Copyright (c) 2015-present Mattermost, Inc. All Rights Reserved.
+// See License.txt for license information.
+
+package invalid
+
+type API interface {
+	// ValidMethod is a fake method for testing the
+	// plugin comment checker with a valid comment.
+	//
+	// Minimum server version: 1.2.3
+	ValidMethod()
+
+	// InvalidMethod is a fake method for testing the
+	// plugin comment checker with an invalid comment.
+	InvalidMethod()
+}