Fix config new command. Closes #1201 (#1202)

Closes #1201

Author: garrytrinder

dev-proxy-abstractions/ProxyUtils.cs

@@ -465,7 +465,7 @@ private static string GetCommonPrefix(List<string> paths)
         var lastSlashIndex = prefix.LastIndexOf('/');
         return lastSlashIndex >= 0 ? prefix[..(lastSlashIndex + 1)] : prefix;
     }
-    
+
     public static async Task<(bool IsValid, IEnumerable<string> ValidationErrors)> ValidateJson(string? json, string? schemaUrl, ILogger logger)
     {
         try
@@ -486,7 +486,7 @@ private static string GetCommonPrefix(List<string> paths)
             logger.LogDebug("Downloading schema from {SchemaUrl}", schemaUrl);
             using var client = new HttpClient();
             var schemaContents = await client.GetStringAsync(schemaUrl);
-            
+
             logger.LogDebug("Parsing schema");
             var schema = JSchema.Parse(schemaContents);
             logger.LogDebug("Parsing JSON");
@@ -517,4 +517,11 @@ public static string ReplaceVariables(string s, Dictionary<string, string> varia
 
         return s1;
     }
+
+    public static string GetVersionString(string productVersion)
+    {
+        return productVersion.Contains("-beta")
+            ? productVersion.Split("-")[0]
+            : productVersion;
+    }
 }

dev-proxy/CommandHandlers/ConfigNewCommandHandler.cs

@@ -17,7 +17,7 @@ public class VisualStudioCodeSnippet
 
 public static class ConfigNewCommandHandler
 {
-    private static readonly string snippetsFileUrl = $"https://aka.ms/devproxy/snippets/v{ProxyUtils.ProductVersion}";
+    private static readonly string snippetsFileUrl = $"https://aka.ms/devproxy/snippets/v{ProxyUtils.GetVersionString(ProxyUtils.ProductVersion)}";
     private static readonly string configFileSnippetName = "ConfigFile";
 
     public static async Task CreateConfigFileAsync(string name, ILogger logger)