Make IsDevelopmentDependency legacy

We should support the OOb SDK Pack property instead.
In this case, it's intuitive enough and will likely get
completion support eventually, as well as docs.

See https://github.com/NuGet/Home/wiki/DevelopmentDependency-support-for-PackageReference

Fixes #253

src/NuGetizer.Tasks/NuGetizer.Compatibility.props

@@ -43,6 +43,8 @@ Copyright (c) .NET Foundation. All rights reserved.
     <PackSymbols Condition="'$(PackSymbols)' == '' and '$(IncludeSymbolsInPackage)' != ''">$(IncludeSymbolsInPackage)</PackSymbols>
     <PackFrameworkReferences Condition="'$(PackFrameworkReferences)' == '' and '$(IncludeFrameworkReferencesInPackage)' != ''">$(IncludeFrameworkReferencesInPackage)</PackFrameworkReferences>
     <PackProjectReferences Condition="'$(PackProjectReferences)' == '' and '$(PackProjectReference)' != ''">true</PackProjectReferences>
+
+    <DevelopmentDependency Condition="'$(IsDevelopmentDependency)' != ''">$(IsDevelopmentDependency)</DevelopmentDependency>
   </PropertyGroup>
 
 </Project>

src/NuGetizer.Tasks/NuGetizer.PackageMetadata.targets

@@ -55,7 +55,7 @@ Copyright (c) .NET Foundation. All rights reserved.
   <ItemDefinitionGroup>
     <PackageMetadata>
       <PackageId>$(PackageId)</PackageId>
-      <DevelopmentDependency Condition="'$(IsDevelopmentDependency)' == 'true'">true</DevelopmentDependency>
+      <DevelopmentDependency>$(DevelopmentDependency)</DevelopmentDependency>
 
       <Authors Condition="'$(Authors)' != ''">$(Authors)</Authors>
       <Owners Condition="'$(Owners)' != ''">$(Owners)</Owners>

src/NuGetizer.Tasks/NuGetizer.Shared.targets

@@ -128,7 +128,7 @@ Copyright (c) .NET Foundation. All rights reserved.
       <!-- By not re-creating the item, we preserve whatever metadata was provided already -->
       <PackageMetadata Include="$(PackageId)" Condition="'@(PackageMetadata)' == ''">
         <PackageId>$(PackageId)</PackageId>
-        <DevelopmentDependency Condition="'$(IsDevelopmentDependency)' == 'true'">true</DevelopmentDependency>
+        <DevelopmentDependency Condition="'$(DevelopmentDependency)' == 'true'">true</DevelopmentDependency>
         <Authors Condition="'$(Authors)' != ''">$(Authors)</Authors>
         <Owners Condition="'$(Owners)' != ''">$(Owners)</Owners>
         <Title Condition="'$(Title)' != ''">$(Title)</Title>

src/NuGetizer.Tasks/NuGetizer.Tasks.targets

@@ -18,7 +18,7 @@
     <Title>NuGetizer</Title>
     <Description>Simple, flexible and powerful NuGet packaging</Description>
 
-    <IsDevelopmentDependency>true</IsDevelopmentDependency>
+    <DevelopmentDependency>true</DevelopmentDependency>
     <PackFolder>build</PackFolder>
 
     <PackOnBuild Condition="'$(PackOnBuild)' == '' And '$(Configuration)' == 'Release'">true</PackOnBuild>

src/NuGetizer.Tests/InlineProjectTests.cs

@@ -32,6 +32,26 @@ public void when_is_packable_true_then_package_id_defaults_to_assembly_name()
             }));
         }
 
+        [Fact]
+        public void when_development_dependency_then_package_has_development_dependency_metadata()
+        {
+            var result = Builder.BuildProject(@"
+<Project Sdk='Microsoft.NET.Sdk'>
+  <PropertyGroup>
+    <IsPackable>true</IsPackable>
+    <TargetFramework>netstandard2.0</TargetFramework>
+    <DevelopmentDependency>true</DevelopmentDependency>
+  </PropertyGroup>
+</Project>", output: output);
+
+            result.AssertSuccess(output);
+            Assert.Contains(result.Items, item => item.Matches(new
+            {
+                PackFolder = PackFolderKind.Metadata,
+                DevelopmentDependency = "true"
+            }));
+        }
+
         [Fact]
         public void when_is_packable_true_but_packageid_reset_to_empty_then_fails()
         {