Fix issue with the default content type as JSON

Author: jdnichollsc

src/Proyecto26.RestClient/Properties/AssemblyInfo.cs

@@ -17,7 +17,7 @@
 // The form "{Major}.{Minor}.*" will automatically update the build and revision,
 // and "{Major}.{Minor}.{Build}.*" will update just the revision.
 
-[assembly: AssemblyVersion ("2.5.3")]
+[assembly: AssemblyVersion ("2.5.4")]
 
 // The following attributes are used to specify the signing key for the assembly,
 // if desired. See the Mono documentation for more information about signing.

src/Proyecto26.RestClient/Proyecto26.RestClient.nuspec

@@ -2,7 +2,7 @@
 <package xmlns="http://schemas.microsoft.com/packaging/2013/05/nuspec.xsd">
   <metadata>
     <id>Proyecto26.RestClient</id>
-    <version>2.5.3</version>
+    <version>2.5.4</version>
     <title>RestClient for Unity</title>
     <authors>Juan David Nicholls Cardona</authors>
     <owners>jdnichollsc</owners>

src/Proyecto26.RestClient/RestClient.cs

@@ -9,7 +9,7 @@ namespace Proyecto26
 {
     /// <summary>
     /// RestClient for Unity
-    /// Version: 2.5.3
+    /// Version: 2.5.4
     /// </summary>
     public static partial class RestClient
     {

src/Proyecto26.RestClient/Utils/HttpBase.cs

@@ -115,8 +115,11 @@ public static IEnumerator DefaultUnityWebRequest<TResponse>(RequestHelper option
         public static IEnumerator SendWebRequest(UnityWebRequest request, RequestHelper options)
         {
             byte[] bodyRaw = options.BodyRaw;
-            string contentType = CONTENT_TYPE_JSON;
-            options.Headers.TryGetValue(CONTENT_TYPE_HEADER, out contentType);
+            string contentType = string.Empty;
+            if (!options.Headers.TryGetValue(CONTENT_TYPE_HEADER, out contentType))
+            {
+                contentType = CONTENT_TYPE_JSON;
+            }
             if (options.Body != null || !string.IsNullOrEmpty(options.BodyString))
             {
                 var bodyString = options.BodyString;