fix: always use lower-cased key to get git config (#2102)

Signed-off-by: leo <longshuang@msn.cn>

Author: love-linger

src/Commands/Config.cs

@@ -1,5 +1,6 @@
 using System;
 using System.Collections.Generic;
+using System.Globalization;
 using System.Threading.Tasks;
 
 namespace SourceGit.Commands
@@ -53,7 +54,11 @@ public async Task<Dictionary<string, string>> ReadAllAsync()
                 {
                     var parts = line.Split('=', 2);
                     if (parts.Length == 2)
-                        rs[parts[0]] = parts[1];
+                    {
+                        var key = parts[0].ToLower(CultureInfo.CurrentCulture); // Always use lower case for key
+                        var value = parts[1];
+                        rs[key] = value;
+                    }
                 }
             }
 

src/ViewModels/Repository.cs

@@ -674,7 +674,7 @@ public void RefreshAll()
                 });
 
                 var config = await new Commands.Config(FullPath).ReadAllAsync().ConfigureAwait(false);
-                _hasAllowedSignersFile = config.TryGetValue("gpg.ssh.allowedSignersFile", out var allowedSignersFile) && !string.IsNullOrEmpty(allowedSignersFile);
+                _hasAllowedSignersFile = config.TryGetValue("gpg.ssh.allowedsignersfile", out var allowedSignersFile) && !string.IsNullOrEmpty(allowedSignersFile);
 
                 if (config.TryGetValue("gitflow.branch.master", out var masterName))
                     GitFlow.Master = masterName;