[DynatraceObservability]Release Api 2021-09-01 version (#19328)

* Move DynatraceObservability to main

* [Dynatrace]add SignatureIssues.csv

Co-authored-by: azure-powershell-bot <[email protected]>

Author: LucasYao93

src/DynatraceObservability/Az.DynatraceObservability.csproj

@@ -0,0 +1,8 @@
+<Project Sdk="Microsoft.NET.Sdk">
+  <PropertyGroup>
+    <PsModuleName>DynatraceObservability</PsModuleName>
+  </PropertyGroup>
+
+  <Import Project="$([MSBuild]::GetDirectoryNameOfFileAbove($(MSBuildThisFileDirectory).., build.proj))\src\Az.autorest.props" />
+  <Import Project="$([MSBuild]::GetDirectoryNameOfFileAbove($(MSBuildThisFileDirectory).., build.proj))\src\Az.Post.props" />
+</Project>