Update to 2.54.0.pre1 on v2.54.x release branch (#2130)

Author: apolcyn

build/version.props

@@ -2,7 +2,7 @@
   <PropertyGroup>
 
     <!-- package version of grpc-dotnet -->
-    <GrpcDotnetVersion>2.54.0-dev</GrpcDotnetVersion>
+    <GrpcDotnetVersion>2.54.0-pre1</GrpcDotnetVersion>
 
     <!-- assembly version of grpc-dotnet -->
     <GrpcDotnetAssemblyVersion>2.0.0.0</GrpcDotnetAssemblyVersion>

src/Grpc.Core.Api/VersionInfo.cs

@@ -41,5 +41,5 @@ public static class VersionInfo
     /// <summary>
     /// Current version of gRPC C#
     /// </summary>
-    public const string CurrentVersion = "2.54.0-dev";
+    public const string CurrentVersion = "2.54.0-pre1";
 }