build: update csproj for 1.3.1

Author: RobynLlama

src/UnityDebuggerAssistant/UnityDebuggerAssistant.csproj

@@ -16,7 +16,7 @@
     <!--
       Except this, you should keep this up to date with your publishing tags.
     -->
-    <Version>1.3.0</Version>
+    <Version>1.3.1</Version>
 
     <!-- 
       You shouldn't have to change these, but you could if you wanted to.