feat: Add support for .NET 9

Author: TheMerski

Dockerfile

@@ -1,9 +1,9 @@
-FROM mcr.microsoft.com/dotnet/aspnet:8.0 as runtime
+FROM mcr.microsoft.com/dotnet/aspnet:9.0 as runtime
 WORKDIR /app
-EXPOSE 80
+EXPOSE 8080
 EXPOSE 443
 
-FROM mcr.microsoft.com/dotnet/sdk:8.0 AS builder-base
+FROM mcr.microsoft.com/dotnet/sdk:9.0 AS builder-base
 WORKDIR /src
 COPY . .
 

GCloud.Compute.Metadata.TestServer/GCloud.Compute.Metadata.TestServer.csproj

@@ -1,10 +1,11 @@
 <Project Sdk="Microsoft.NET.Sdk.Web">
 
   <PropertyGroup>
-    <TargetFramework>net8.0</TargetFramework>
+    <TargetFramework>net9.0</TargetFramework>
     <Nullable>enable</Nullable>
     <ImplicitUsings>enable</ImplicitUsings>
     <DockerDefaultTargetOS>Linux</DockerDefaultTargetOS>
+    <LangVersion>13</LangVersion>
   </PropertyGroup>
 
   <ItemGroup>

GCloud.Compute.Metadata.Tests/GCloud.Compute.Metadata.Tests.csproj

@@ -1,12 +1,13 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
     <PropertyGroup>
-        <TargetFramework>net8.0</TargetFramework>
         <ImplicitUsings>enable</ImplicitUsings>
         <Nullable>enable</Nullable>
 
         <IsPackable>false</IsPackable>
         <IsTestProject>true</IsTestProject>
+        <TargetFrameworks>net8.0;net9.0</TargetFrameworks>
+        <LangVersion>13</LangVersion>
     </PropertyGroup>
 
     <ItemGroup>

GCloud.Compute.Metadata.V1/GCloud.Compute.Metadata.V1.csproj

@@ -1,7 +1,6 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
     <PropertyGroup>
-        <TargetFramework>net8.0</TargetFramework>
         <ImplicitUsings>enable</ImplicitUsings>
         <Nullable>enable</Nullable>
         <PackageId>GCloud.Compute.Metadata.V1</PackageId>
@@ -16,6 +15,8 @@
         <Description>Library for using the GCE metadata api</Description>
         <GeneratePackageOnBuild>true</GeneratePackageOnBuild>
         <PackageTags>google cloud metadata</PackageTags>
+        <LangVersion>13</LangVersion>
+        <TargetFrameworks>net9.0;net8.0</TargetFrameworks>
     </PropertyGroup>
     <ItemGroup>
     <None Include="..\LICENSE">