Add operators : Not Like, Start With, Not Start with, End With, Not …

src/JsonApiDotNetCore/Extensions/IQueryableExtensions.cs

@@ -149,7 +149,28 @@ private static Expression GetFilterExpressionLambda(Expression left, Expression
                     body = Expression.GreaterThanOrEqual(left, right);
                     break;
                 case FilterOperation.like:
-                    body = Expression.Call(left, "Contains", null, right);
+                case FilterOperation.notlike:
+                    body = Expression.Call(left, nameof(string.Contains), null, right);
+                    if(operation== FilterOperation.notlike)
+                    {
+                        body = Expression.Not(body);
+                    }
+                    break;
+                case FilterOperation.sw:
+                case FilterOperation.notsw:
+                    body = Expression.Call(left, nameof(string.StartsWith), null, right);
+                    if (operation == FilterOperation.notsw)
+                    {
+                        body = Expression.Not(body);
+                    }
+                    break;
+                case FilterOperation.ew:
+                case FilterOperation.notew:
+                    body = Expression.Call(left, nameof(string.EndsWith), null, right);
+                    if (operation == FilterOperation.notew)
+                    {
+                        body = Expression.Not(body);
+                    }
                     break;
                 // {model.Id != 1}
                 case FilterOperation.ne:

src/JsonApiDotNetCore/Internal/Query/FilterOperations.cs

@@ -13,6 +13,11 @@ public enum FilterOperation
         @in = 7, // prefix with @ to use keyword
         nin = 8,
         isnull = 9,
-        isnotnull = 10
+        isnotnull = 10,
+        notlike = 11,
+        sw = 12, //start with
+        notsw = 13, //doesn't start with
+        ew = 14, // end with,
+        notew = 15 // doesn't end with
     }
 }