Refactor Git branch retrieval and push operations

Revised the Git branch retrieval process to include fetching remote branches if not found locally. Improved the Push method by refactoring branch retrieval and updating the PushOptions initialization for better readability and maintainability.

src/DependencyUpdated.Repositories.AzureDevOps/AzureDevOps.cs

@@ -61,9 +61,9 @@ public void CommitChanges(string repositoryPath, string projectName, string grou
         var author = new Signature(config.Value.AzureDevOps.Username, config.Value.AzureDevOps.Email,
             timeProvider.GetUtcNow());
         repo.Commit(GitCommitMessage, author, author);
-        var options = new PushOptions();
-        options.CredentialsProvider = CreateGitCredentialsProvider();
-        repo.Network.Push(repo.Branches[gitBranchName], options);
+        var branch = GetGitBranch(repo, gitBranchName);
+        var options = new PushOptions { CredentialsProvider = CreateGitCredentialsProvider() };
+        repo.Network.Push(branch, options);
     }
 
     public async Task SubmitPullRequest(IReadOnlyCollection<UpdateResult> updates, string projectName, string group)
@@ -149,14 +149,15 @@ private static string CreateGitBranchName(string projectName, string branchName,
 
     private Branch? GetGitBranch(Repository repo, string branchName)
     {
+        var options = new FetchOptions { CredentialsProvider = CreateGitCredentialsProvider() };
+        Commands.Fetch(repo, RemoteName, ArraySegment<string>.Empty, options, string.Empty);
+
         var branch = repo.Branches[branchName];
         if (branch is not null)
         {
             return branch;
         }
-
-        var options = new FetchOptions { CredentialsProvider = CreateGitCredentialsProvider() };
-        Commands.Fetch(repo, RemoteName, ArraySegment<string>.Empty, options, string.Empty);
+
         return repo.Branches[$"{RemoteName}/{branchName}"];
     }