Drop net45

Source/Apos.Input.csproj

@@ -1,6 +1,6 @@
 <Project Sdk="Microsoft.NET.Sdk">
   <PropertyGroup>
-    <TargetFrameworks>netstandard2.0;net45</TargetFrameworks>
+    <TargetFramework>netstandard2.0</TargetFramework>
     <PackageId>Apos.Input</PackageId>
     <Title>Apos.Input</Title>
     <Version>0.4.0</Version>