Use proxy for pull mirror (#22771) (#22772)

- Backport #22771
  - Use the proxy (if one is specified) for pull mirrors syncs.
- Pulled the code from
c2774d9e80/modules/git/repo.go (L164-L170)
  - Downstream issue: https://codeberg.org/forgejo/forgejo/issues/302

---------

Co-authored-by: zeripath <art27@cantab.net>

services/mirror/mirror_pull.go

@@ -19,6 +19,7 @@ import (
 	"code.gitea.io/gitea/modules/log"
 	"code.gitea.io/gitea/modules/notification"
 	"code.gitea.io/gitea/modules/process"
+	"code.gitea.io/gitea/modules/proxy"
 	repo_module "code.gitea.io/gitea/modules/repository"
 	"code.gitea.io/gitea/modules/setting"
 	"code.gitea.io/gitea/modules/timeutil"
@@ -216,6 +217,8 @@ func runSync(ctx context.Context, m *repo_model.Mirror) ([]*mirrorSyncResult, bo
 		return nil, false
 	}
 
+	envs := proxy.EnvWithProxy(remoteURL.URL)
+
 	stdoutBuilder := strings.Builder{}
 	stderrBuilder := strings.Builder{}
 	if err := git.NewCommand(ctx, gitArgs...).
@@ -223,6 +226,7 @@ func runSync(ctx context.Context, m *repo_model.Mirror) ([]*mirrorSyncResult, bo
 		Run(&git.RunOpts{
 			Timeout: timeout,
 			Dir:     repoPath,
+			Env:     envs,
 			Stdout:  &stdoutBuilder,
 			Stderr:  &stderrBuilder,
 		}); err != nil {