Update API approvals

Author: Shane32

QRCoderApiTests/net35+net40+net50+net50-windows+netstandard20/QRCoder.approved.txt

@@ -967,10 +967,12 @@ namespace QRCoder.Exceptions
 }
 namespace QRCoder.Extensions
 {
+    [System.Obsolete("This class will be removed in a future version of QRCoder.")]
     public static class CustomExtensions
     {
         public static string GetStringValue(this System.Enum value) { }
     }
+    [System.Obsolete("This attribute will be removed in a future version of QRCoder.")]
     public class StringValueAttribute : System.Attribute
     {
         public StringValueAttribute(string value) { }

QRCoderApiTests/net60-windows/QRCoder.approved.txt

@@ -977,10 +977,13 @@ namespace QRCoder.Exceptions
 }
 namespace QRCoder.Extensions
 {
+    [System.Obsolete("This class will be removed in a future version of QRCoder.")]
     public static class CustomExtensions
     {
+        [System.Diagnostics.CodeAnalysis.RequiresUnreferencedCode("This method uses reflection to examine the provided enum value.")]
         public static string GetStringValue(this System.Enum value) { }
     }
+    [System.Obsolete("This attribute will be removed in a future version of QRCoder.")]
     public class StringValueAttribute : System.Attribute
     {
         public StringValueAttribute(string value) { }

QRCoderApiTests/net60/QRCoder.approved.txt

@@ -904,10 +904,13 @@ namespace QRCoder.Exceptions
 }
 namespace QRCoder.Extensions
 {
+    [System.Obsolete("This class will be removed in a future version of QRCoder.")]
     public static class CustomExtensions
     {
+        [System.Diagnostics.CodeAnalysis.RequiresUnreferencedCode("This method uses reflection to examine the provided enum value.")]
         public static string GetStringValue(this System.Enum value) { }
     }
+    [System.Obsolete("This attribute will be removed in a future version of QRCoder.")]
     public class StringValueAttribute : System.Attribute
     {
         public StringValueAttribute(string value) { }

QRCoderApiTests/netstandard13/QRCoder.approved.txt

@@ -831,10 +831,12 @@ namespace QRCoder.Exceptions
 }
 namespace QRCoder.Extensions
 {
+    [System.Obsolete("This class will be removed in a future version of QRCoder.")]
     public static class CustomExtensions
     {
         public static string GetStringValue(this System.Enum value) { }
     }
+    [System.Obsolete("This attribute will be removed in a future version of QRCoder.")]
     public class StringValueAttribute : System.Attribute
     {
         public StringValueAttribute(string value) { }