Prevent breaking change on optional parameter #487

Author: CumpsD

src/Microsoft.OpenApi/Any/OpenApiString.cs

@@ -10,12 +10,21 @@ public class OpenApiString : OpenApiPrimitive<string>
     {
         private bool isExplicit;
 
+        /// <summary>
+        /// Initializes the <see cref="OpenApiString"/> class.
+        /// </summary>
+        /// <param name="value"></param>
+        public OpenApiString(string value)
+            : this(value, false)
+        {
+        }
+        
         /// <summary>
         /// Initializes the <see cref="OpenApiString"/> class.
         /// </summary>
         /// <param name="value"></param>
         /// <param name="isExplicit">Used to indicate if a string is quoted.</param>
-        public OpenApiString(string value, bool isExplicit = false)
+        public OpenApiString(string value, bool isExplicit)
             : base(value)
         {
             this.isExplicit = isExplicit;