refactor: centralize version in Directory.Build.props

Remove VersionPrefix from individual .fsproj files to inherit from
src/Directory.Build.props, ensuring consistent versioning across all
packages.

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

Author: panesofglass

src/FSharp.Data.JsonSchema.Core/FSharp.Data.JsonSchema.Core.fsproj

@@ -2,7 +2,6 @@
 
   <PropertyGroup>
     <TargetFrameworks>netstandard2.0;netstandard2.1;netcoreapp3.1;net6.0;net8.0;net9.0;net10.0</TargetFrameworks>
-    <VersionPrefix>3.0.0</VersionPrefix>
     <PackageId Condition="$(GITHUB_REPOSITORY_OWNER) != 'fsprojects' and $(GITHUB_REPOSITORY_OWNER) != ''">$(GITHUB_REPOSITORY_OWNER).FSharp.Data.JsonSchema.Core</PackageId>
     <Description>Target-agnostic JSON Schema IR and type analyzer for F# types. Use this package to analyze F# types into a schema document and translate to any target format.</Description>
   </PropertyGroup>

src/FSharp.Data.JsonSchema.NJsonSchema/FSharp.Data.JsonSchema.NJsonSchema.fsproj

@@ -2,7 +2,6 @@
 <Project Sdk="Microsoft.NET.Sdk">
   <PropertyGroup>
     <TargetFrameworks>netstandard2.0;netstandard2.1;netcoreapp3.1;net6.0;net8.0;net9.0;net10.0</TargetFrameworks>
-    <VersionPrefix>3.0.0</VersionPrefix>
     <PackageId Condition="$(GITHUB_REPOSITORY_OWNER) != 'fsprojects' and $(GITHUB_REPOSITORY_OWNER) != ''">$(GITHUB_REPOSITORY_OWNER).FSharp.Data.JsonSchema.NJsonSchema</PackageId>
     <Description>NJsonSchema-based JSON Schema generation for F# types. This package provides Generator.Create/CreateMemoized for generating NJsonSchema.JsonSchema from F# types, with support for records, discriminated unions, and validation.</Description>
   </PropertyGroup>

src/FSharp.Data.JsonSchema.OpenApi/FSharp.Data.JsonSchema.OpenApi.fsproj

@@ -2,7 +2,6 @@
 
   <PropertyGroup>
     <TargetFrameworks>net9.0;net10.0</TargetFrameworks>
-    <VersionPrefix>3.0.0</VersionPrefix>
     <PackageId Condition="$(GITHUB_REPOSITORY_OWNER) != 'fsprojects' and $(GITHUB_REPOSITORY_OWNER) != ''">$(GITHUB_REPOSITORY_OWNER).FSharp.Data.JsonSchema.OpenApi</PackageId>
     <Description>OpenAPI schema translator for F# types. Provides IOpenApiSchemaTransformer for ASP.NET Core OpenAPI integration using FSharp.Data.JsonSchema.Core.</Description>
   </PropertyGroup>

src/FSharp.Data.JsonSchema/FSharp.Data.JsonSchema.fsproj

@@ -2,7 +2,6 @@
 <Project Sdk="Microsoft.NET.Sdk">
   <PropertyGroup>
     <TargetFrameworks>netstandard2.0;netstandard2.1;netcoreapp3.1;net6.0;net8.0;net9.0;net10.0</TargetFrameworks>
-    <VersionPrefix>3.0.0</VersionPrefix>
     <PackageId Condition="$(GITHUB_REPOSITORY_OWNER) != 'fsprojects' and $(GITHUB_REPOSITORY_OWNER) != ''">$(GITHUB_REPOSITORY_OWNER).FSharp.Data.JsonSchema</PackageId>
     <Description>[DEPRECATED] This package has been renamed to FSharp.Data.JsonSchema.NJsonSchema. Please upgrade to the new package name. This package will not receive updates beyond 3.0.0.</Description>
   </PropertyGroup>