[build] Revert to https cloning for changelog

Author: AndreyAkinshin

build/BenchmarkDotNet.Build/Meta/Repo.cs

@@ -10,7 +10,7 @@ public static class Repo
     public const string Owner = "dotnet";
     public const string Name = "BenchmarkDotNet";
     public const string HttpsUrlBase = $"https://github.com/{Owner}/{Name}";
-    public const string SshGitUrl =  $"git@github.com:{Owner}/{Name}.git";
+    public const string HttpsGitUrl =  $"{HttpsUrlBase}.git";
 
     public const string ChangelogBranch = "docs-changelog";
     public const string DocsStableBranch = "docs-stable";

build/BenchmarkDotNet.Build/Runners/Changelog/ChangelogBuilder.cs

@@ -244,8 +244,8 @@ private void EnsureSrcDirectoryExist(bool forceClone = false)
 
         if (!context.DirectoryExists(SrcDirectory))
         {
-            Log($"Cloning branch '{Repo.ChangelogBranch}' from '{Repo.SshGitUrl}' to '{SrcDirectory}'.");
-            context.GitRunner.Clone(SrcDirectory, Repo.SshGitUrl, Repo.ChangelogBranch);
+            Log($"Cloning branch '{Repo.ChangelogBranch}' from '{Repo.HttpsGitUrl}' to '{SrcDirectory}'.");
+            context.GitRunner.Clone(SrcDirectory, Repo.HttpsGitUrl, Repo.ChangelogBranch);
             Log($"Clone completed: '{Repo.ChangelogBranch}' -> '{SrcDirectory}'.");
         }
         else