Retarget from net462 to net472

This allows us to update our libgit2sharp dependency. And while projects that use NB.GV may *target* net462 without a problem, NB.GV requiring that build machines have at least net472 installed seems totally reasonable.

Author: AArnott

src/NerdBank.GitVersioning/ManagedGit/GitPackDeltafiedStream.cs

@@ -65,7 +65,7 @@ public override long Position
         set => throw new NotImplementedException();
     }
 
-#if NETSTANDARD2_0
+#if NETFRAMEWORK
     /// <summary>
     /// Reads a sequence of bytes from the current <see cref="GitPackDeltafiedStream"/> and advances the position
     /// within the stream by the number of bytes read.

src/NerdBank.GitVersioning/ManagedGit/GitPackMemoryCacheStream.cs

@@ -44,7 +44,7 @@ public override void Flush()
         throw new NotSupportedException();
     }
 
-#if NETSTANDARD2_0
+#if NETFRAMEWORK
     public int Read(Span<byte> buffer)
 #else
     /// <inheritdoc/>

src/NerdBank.GitVersioning/ManagedGit/GitPackMemoryCacheViewStream.cs

@@ -42,7 +42,7 @@ public override int Read(byte[] buffer, int offset, int count)
         return this.Read(buffer.AsSpan(offset, count));
     }
 
-#if NETSTANDARD2_0
+#if NETFRAMEWORK
     public int Read(Span<byte> buffer)
 #else
     /// <inheritdoc/>

src/NerdBank.GitVersioning/ManagedGit/GitPackPooledStream.cs

@@ -62,7 +62,7 @@ public override void Flush()
         this.stream.Flush();
     }
 
-#if !NETSTANDARD2_0
+#if NET6_0_OR_GREATER
     /// <inheritdoc/>
     public override int Read(Span<byte> buffer)
     {

src/NerdBank.GitVersioning/ManagedGit/GitRepository.cs

@@ -668,7 +668,7 @@ public void Dispose()
 
     private static string TrimEndingDirectorySeparator(string path)
     {
-#if NETSTANDARD2_0
+#if NETFRAMEWORK
         if (string.IsNullOrEmpty(path) || path.Length == 1)
         {
             return path;
@@ -699,7 +699,7 @@ private static bool TryConvertHexStringToByteArray(string hexString, Span<byte>
         Requires.Argument(data.Length == hexString.Length / 2, nameof(data), "Length must be exactly half that of " + nameof(hexString) + ".");
         for (int index = 0; index < data.Length; index++)
         {
-#if !NETSTANDARD2_0
+#if NET6_0_OR_GREATER
             ReadOnlySpan<char> byteValue = hexString.AsSpan(index * 2, 2);
             if (!byte.TryParse(byteValue, NumberStyles.HexNumber, CultureInfo.InvariantCulture, out data[index]))
             {

src/NerdBank.GitVersioning/ManagedGit/MemoryMappedStream.cs

@@ -73,7 +73,7 @@ public override int Read(byte[] buffer, int offset, int count)
         return read;
     }
 
-#if !NETSTANDARD2_0
+#if NET6_0_OR_GREATER
     /// <inheritdoc/>
     public override int Read(Span<byte> buffer)
     {

src/NerdBank.GitVersioning/ManagedGit/StreamExtensions.cs

@@ -78,7 +78,7 @@ public static int ReadMbsInt(this Stream stream)
         return value;
     }
 
-#if NETSTANDARD2_0
+#if NETFRAMEWORK
     /// <summary>
     /// Reads a sequence of bytes from the current stream and advances the position within the stream by
     /// the number of bytes read.

src/NerdBank.GitVersioning/ManagedGit/ZLibStream.cs

@@ -92,7 +92,7 @@ public override int Read(byte[] array, int offset, int count)
         return read;
     }
 
-#if !NETSTANDARD2_0
+#if NET6_0_OR_GREATER
     /// <inheritdoc/>
     public override int Read(Span<byte> buffer)
     {
@@ -110,7 +110,7 @@ public override async Task<int> ReadAsync(byte[] array, int offset, int count, C
         return read;
     }
 
-#if !NETSTANDARD2_0
+#if NET6_0_OR_GREATER
     /// <inheritdoc/>
     public override async ValueTask<int> ReadAsync(Memory<byte> buffer, CancellationToken cancellationToken = default)
     {

src/NerdBank.GitVersioning/Nerdbank.GitVersioning.csproj

@@ -1,6 +1,6 @@
 <Project Sdk="Microsoft.NET.Sdk">
   <PropertyGroup>
-    <TargetFrameworks>netstandard2.0;net6.0</TargetFrameworks>
+    <TargetFrameworks>net472;net6.0</TargetFrameworks>
     <GenerateDocumentationFile>true</GenerateDocumentationFile>
     <DebugType>Full</DebugType>
     <IsPackable>false</IsPackable>

src/Nerdbank.GitVersioning.Tasks/AssemblyVersionInfo.cs

@@ -37,7 +37,7 @@ the code is regenerated.
 ------------------------------------------------------------------------------
 ";
 
-#if NET462
+#if NETFRAMEWORK
         private static readonly CodeGeneratorOptions CodeGeneratorOptions = new CodeGeneratorOptions
         {
             BlankLinesBetweenMembers = false,
@@ -136,7 +136,7 @@ public string BuildCode()
             return null;
         }
 
-#if NET462
+#if NETFRAMEWORK
         /// <inheritdoc/>
         public override bool Execute()
         {
@@ -186,7 +186,7 @@ public override bool Execute()
         }
 #endif
 
-#if !NET462
+#if !NETFRAMEWORK
         /// <inheritdoc/>
         public override bool Execute()
         {
@@ -233,7 +233,7 @@ private static byte[] GetPublicKeyFromKeyPair(byte[] keyPair)
             }
         }
 
-#if NET462
+#if NETFRAMEWORK
         private static CodeMemberField CreateField<T>(string name, T value)
         {
             return new CodeMemberField(typeof(T), name)