Mark DateTimeExtensions methods as obsolete DuendeSoftware/foss#56

Author: maartenba

src/content/docs/identitymodel/utils/epoch-time.md

@@ -5,22 +5,27 @@ description: Learn about converting between DateTime and Unix/Epoch time formats
 sidebar:
   label: "Epoch Time"
   order: 3
+  badge:
+    text: deprecated
+    variant: note
 redirect_from:
   - /foss/identitymodel/utils/epoch_time/
 ---
 
-:::note
+:::note[Deprecation notice]
 Starting with .NET Framework 4.6 and .NET Core 1.0 this functionality is
 built-in via
-[DateTimeOffset.FromUnixTimeSeconds](https://docs.microsoft.com/en-us/dotnet/api/system.datetimeoffset.fromunixtimeseconds)
+[`DateTimeOffset.FromUnixTimeSeconds`](https://docs.microsoft.com/en-us/dotnet/api/system.datetimeoffset.fromunixtimeseconds)
 and
-[DateTimeOffset.ToUnixTimeSeconds](https://docs.microsoft.com/en-us/dotnet/api/system.datetimeoffset.tounixtimeseconds).
+[`DateTimeOffset.ToUnixTimeSeconds`](https://docs.microsoft.com/en-us/dotnet/api/system.datetimeoffset.tounixtimeseconds).
+
+The `DateTimeExtensions` will be removed from Duende IdentityModel in the future.
 :::
 
 JSON Web Token (JWT) tokens use so-called [Epoch or Unix time](https://en.wikipedia.org/wiki/Unix_time) to represent
 date/times, which is the number of seconds that have elapsed since January 1, 1970 (midnight UTC/GMT).
 
-## DateTimeOffset To Epoch Time
+## DateTimeOffset To Epoch Time :badge[Obsolete]
 
 In .NET, you can convert `DateTimeOffset` to Unix time via the two methods of `ToUnixTimeSeconds` and
 `ToUnixTimeMilliseconds`:
@@ -31,7 +36,7 @@ var seconds = DateTimeOffset.UtcNow.ToUnixTimeSeconds();
 var milliseconds = DateTimeOffset.UtcNow.ToUnixTimeMilliseconds();
 ```
 
-## DateTime To Epoch Time :badge[obsolete]
+## DateTime To Epoch Time :badge[Obsolete]
 
 IdentityModel contains extensions methods for `DateTime` to convert
 to/from Unix time: