build: suppress MA0158 - will not work in .netstandard2.1

Author: Per Kops

src/Atc/Helpers/CultureHelper.cs

@@ -8,6 +8,7 @@ namespace Atc.Helpers;
 /// CultureHelper.
 /// </summary>
 [SuppressMessage("Design", "CA1002:Do not expose generic lists", Justification = "OK.")]
+[SuppressMessage("", "MA0158:System.Threading.Lock", Justification = "OK.")]
 [SuppressMessage("StyleCop.CSharp.DocumentationRules", "SA1615:Element return value should be documented", Justification = "OK.")]
 public static class CultureHelper
 {

src/Atc/Helpers/RegionInfoHelper.cs

@@ -3,6 +3,7 @@ namespace Atc.Helpers;
 /// <summary>
 /// RegionInfoHelper.
 /// </summary>
+[SuppressMessage("", "MA0158:System.Threading.Lock", Justification = "OK.")]
 public static class RegionInfoHelper
 {
     private static readonly object Lock = new();