Use NBGV for package versioning

Core/MonoDevelop.Xml.Core.csproj

@@ -7,7 +7,6 @@
   <PropertyGroup>
     <GeneratePackageOnBuild>True</GeneratePackageOnBuild>
     <PackageId>MonoDevelop.Xml.Core</PackageId>
-    <Version>1.0.0</Version>
     <Authors>mhutch, Microsoft</Authors>
     <Company>Microsoft</Company>
     <Summary>A full-fidelity XML parser</Summary>

Directory.Build.props

@@ -9,4 +9,8 @@
     <EmbedUntrackedSources>true</EmbedUntrackedSources>
   </PropertyGroup>
 
+  <ItemGroup>
+    <PackageReference Include="Nerdbank.GitVersioning" Version="3.5.107" PrivateAssets="all" />
+  </ItemGroup>
+
 </Project>

Editor/MonoDevelop.Xml.Editor.csproj

@@ -11,7 +11,6 @@
   <PropertyGroup>
     <GeneratePackageOnBuild>True</GeneratePackageOnBuild>
     <PackageId>MonoDevelop.Xml.Editor</PackageId>
-    <Version>1.0.0</Version>
     <Authors>mhutch, Microsoft</Authors>
     <Company>Microsoft</Company>
     <Summary>A full-fidelity XML language service</Summary>

version.json

@@ -0,0 +1,18 @@
+{
+    "$schema": "https://raw.githubusercontent.com/dotnet/Nerdbank.GitVersioning/master/src/NerdBank.GitVersioning/version.schema.json",
+    "version": "1.0.0",
+    "publicReleaseRefSpec": [
+      "^refs/tags/v\\d+\\.\\d+$",
+      "^refs/tags/v\\d+\\.\\d+\\.\\d+$"
+    ],
+    "cloudBuild": {
+      "buildNumber": {
+        "enabled": true
+      }
+    },
+    "release": {
+      "branchName": "release/v{version}",
+      "firstUnstableTag": "preview"
+    }
+  }
+