Update BouncyCastle.Cryptography to 2.5.1

Author: cYKatherine

UID2.Client.nuspec

@@ -19,7 +19,7 @@
     <dependencies>
       <group targetFramework=".NETStandard2.0">
         <dependency id="NETStandard.Library" version="[2.0.0, )" />
-        <dependency id="BouncyCastle.Cryptography" version="2.2.1" exclude="Build,Analyzers" />
+        <dependency id="BouncyCastle.Cryptography" version="2.5.1" exclude="Build,Analyzers" />
         <dependency id="Microsoft.IdentityModel.Tokens" version="5.3.0" exclude="Build,Analyzers" />
         <dependency id="Newtonsoft.Json" version="13.0.1" exclude="Build,Analyzers" />
       </group>