Update README.md

[ci skip]

src/Microsoft.DotNet.Watcher.Tools/README.md

@@ -8,7 +8,7 @@ Install `Microsoft.DotNet.Watcher.Tools` as a `DotNetCliToolReference` to your p
 
 ```xml
   <ItemGroup>
-    <DotNetCliToolReference Include="Microsoft.DotNet.Watcher.Tools" Version="1.0.0-msbuild2-final" />
+    <DotNetCliToolReference Include="Microsoft.DotNet.Watcher.Tools" Version="1.0.0-msbuild3-final" />
   </ItemGroup>
 ```
 
@@ -95,4 +95,4 @@ Example:
   <ItemGroup Condition="'$(DotNetWatchBuild)'=='true'">
     <!-- only included in the project when dotnet-watch is running -->
   </ItemGroup>
-```
+```