Treat rtm as stable Fixes #36500 (#37160)

Author: Forgind

src/Resolvers/Microsoft.NET.Sdk.WorkloadManifestReader/SdkFeatureBand.cs

@@ -15,7 +15,7 @@ public struct SdkFeatureBand : IEquatable<SdkFeatureBand>, IComparable<SdkFeatur
         public SdkFeatureBand(ReleaseVersion version)
         {
             var fullVersion = version ?? throw new ArgumentNullException(nameof(version));
-            if (string.IsNullOrEmpty(version.Prerelease) || version.Prerelease.Contains("dev") || version.Prerelease.Contains("ci"))
+            if (string.IsNullOrEmpty(version.Prerelease) || version.Prerelease.Contains("dev") || version.Prerelease.Contains("ci") || version.Prerelease.Contains("rtm"))
             {
                 _featureBand = new ReleaseVersion(fullVersion.Major, fullVersion.Minor, fullVersion.SdkFeatureBand);
             }