azp: always transform filepath using RelativeTo (#258)

Absolute path can just use cwd / or .

src/Sdk/AzurePipelines/AzureDevops.cs

@@ -467,7 +467,7 @@ public static async Task<MappingToken> ReadTemplate(Runner.Server.Azure.Devops.C
         var fileId = templateContext.GetFileId(filename);
         // Read the file
         var finalRepository = afilenameAndRef.Length == 1 ? context.RepositoryAndRef : string.Equals(afilenameAndRef[1], "self", StringComparison.OrdinalIgnoreCase) ? null : (context.Repositories?.TryGetValue(afilenameAndRef[1], out var ralias) ?? false) ? ralias : throw new Exception($"Couldn't find repository with alias {afilenameAndRef[1]} in repository resources");
-        var finalFileName = context.RepositoryAndRef == finalRepository ? RelativeTo(context.CWD ?? ".", filename) : filename;
+        var finalFileName = RelativeTo(context.RepositoryAndRef == finalRepository ? context.CWD ?? "." : "/", filename);
         if(finalFileName == null) {
             throw new Exception($"Couldn't find template location {filenameAndRef}");
         }