Fix bug decoding ASN integers. Fixes #1242

This introduces a regression introduced in 0bb5885 for older TFMs.

Author: bgrainger

src/MySqlConnector/Utilities/Utility.cs

@@ -653,7 +653,7 @@ private static bool TryReadAsnInteger(ReadOnlySpan<byte> data, out ReadOnlySpan<
 		bytesConsumed = lengthBytesConsumed + length + 1;
 
 		// trim leading zero bytes
-		while (number is [ 0, .. ])
+		while (number is [ 0, _, .. ])
 			number = number[1..];
 
 		return true;

tests/MySqlConnector.Tests/MySqlConnector.Tests.csproj

@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup Condition=" '$(Configuration)' != 'MySqlData' ">
-    <TargetFrameworks>net7.0</TargetFrameworks>
+    <TargetFrameworks>netcoreapp3.1;net7.0</TargetFrameworks>
   </PropertyGroup>
 
  <PropertyGroup Condition=" '$(Configuration)' == 'MySqlData' ">

tests/MySqlConnector.Tests/UtilityTests.cs

@@ -110,9 +110,13 @@ public void ParseTimeSpanFails(string input)
 	[InlineData("pre", "post")]
 	public void DecodePublicKey(string pre, string post)
 	{
+#if NET5_0_OR_GREATER
 		using var rsa = RSA.Create();
 		Utility.LoadRsaParameters(pre + c_publicKey + post, rsa);
 		var parameters = rsa.ExportParameters(false);
+#else
+		var parameters = Utility.GetRsaParameters(pre + c_publicKey + post);
+#endif
 		Assert.Equal(s_modulus, parameters.Modulus);
 		Assert.Equal(s_exponent, parameters.Exponent);
 	}
@@ -124,9 +128,13 @@ public void DecodePublicKey(string pre, string post)
 	[InlineData("pre", "post")]
 	public void DecodePrivateKey(string pre, string post)
 	{
+#if NET5_0_OR_GREATER
 		using var rsa = RSA.Create();
 		Utility.LoadRsaParameters(pre + c_privateKey + post, rsa);
 		var parameters = rsa.ExportParameters(true);
+#else
+		var parameters = Utility.GetRsaParameters(pre + c_privateKey + post);
+#endif
 		Assert.Equal(s_modulus, parameters.Modulus);
 		Assert.Equal(s_exponent, parameters.Exponent);
 		Assert.Equal(s_d, parameters.D);