Update 1 nuget dependencies

Author: github-actions[bot]

nanoFramework.Aws.IoTCore.Devices.nuspec

@@ -22,7 +22,7 @@ This is an SDK for Aws IoTCore.</description>
     <dependencies>
       <dependency id="nanoFramework.CoreLibrary" version="1.10.5" />
       <dependency id="nanoFramework.Json" version="2.1.0" />
-      <dependency id="nanoFramework.M2Mqtt" version="5.0.2-preview.12" />
+      <dependency id="nanoFramework.M2Mqtt" version="5.0.2-preview.15" />
       <dependency id="nanoFramework.Runtime.Events" version="1.9.2-preview.5" />
       <dependency id="nanoFramework.Runtime.Native" version="1.5.1" />
       <dependency id="nanoFramework.System.Collections" version="1.2.0" />

nanoFramework.Aws.IoTCore.Devices/nanoFramework.Aws.IoTCore.Devices.nfproj

@@ -55,7 +55,7 @@
       <SpecificVersion>True</SpecificVersion>
     </Reference>
     <Reference Include="nanoFramework.M2Mqtt, Version=5.0.2.0, Culture=neutral, PublicKeyToken=c07d481e9758c731">
-      <HintPath>..\packages\nanoFramework.M2Mqtt.5.0.2-preview.12\lib\nanoFramework.M2Mqtt.dll</HintPath>
+      <HintPath>..\packages\nanoFramework.M2Mqtt.5.0.2-preview.15\lib\nanoFramework.M2Mqtt.dll</HintPath>
       <Private>True</Private>
     </Reference>
     <Reference Include="nanoFramework.Runtime.Events, Version=1.9.2.0, Culture=neutral, PublicKeyToken=c07d481e9758c731">

nanoFramework.Aws.IoTCore.Devices/packages.config

@@ -2,7 +2,7 @@
 <packages>
   <package id="nanoFramework.CoreLibrary" version="1.10.5" targetFramework="netnanoframework10" />
   <package id="nanoFramework.Json" version="2.1.0" targetFramework="netnanoframework10" />
-  <package id="nanoFramework.M2Mqtt" version="5.0.2-preview.12" targetFramework="netnanoframework10" />
+  <package id="nanoFramework.M2Mqtt" version="5.0.2-preview.15" targetFramework="netnanoframework10" />
   <package id="nanoFramework.Runtime.Events" version="1.9.2-preview.5" targetFramework="netnanoframework10" />
   <package id="nanoFramework.Runtime.Native" version="1.5.1" targetFramework="netnanoframework10" />
   <package id="nanoFramework.System.Collections" version="1.2.0" targetFramework="netnanoframework10" />