Update for version 1.8.0 (#6)

- Bump library version
- Bump htmx script version
- Add hx-replace-url / HX-Replace-Url
- Add hx-select-oob
- Change hx-push-url to accept a string
- Add HX-Push-Url, obsolete HX-Push
- Implement HX-Reswap header
- Rework project structure to add common project

src/ViewEngine.Htmx.Tests/Giraffe.ViewEngine.Htmx.Tests.fsproj

@@ -1,8 +1,6 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <TargetFramework>net6.0</TargetFramework>
-
     <IsPackable>false</IsPackable>
     <GenerateProgramFile>false</GenerateProgramFile>
   </PropertyGroup>