chore(deps): bump go-acme/lego to v5.2.1 (#12909)

lego v5.2.1 (released 2026-06-01) is a small follow-up patch on top of v5.2.0; the only fixed item is a CLI/migration ergonomics tweak (printing the suggested configuration when the file cannot be created) that does not affect 1Panel, but moving to the latest tag keeps us on a published release rather than the previous one.

Changes are confined to agent/go.mod and agent/go.sum; the source files under agent/utils/ssl/ already use the import path github.com/go-acme/lego/v5/... and require no code changes. Compared with the previous v5.2.0 step, this revision is a 6-line dependency bump (1 line in go.mod plus 4 lines of refreshed go.sum hashes), since lego itself did not move any of its own dependency pins between v5.2.0 and v5.2.1.

Indirect dependency bumps (carried over from the v5.2.0 -> v5.2.1 rebase, produced by 'go mod tidy' on a fresh checkout):

- alibabacloud-go/darabonba-openapi v2.1.16 -> v2.2.1, alibabacloud-go/tea v1.4.0 -> v1.5.0 (alidns provider chain)

- aws-sdk-go-v2 family v1.41.7 -> v1.41.8 plus matching service modules (route53 provider chain)

- baidubce/bce-sdk-go v0.9.266 -> v0.9.267, huaweicloud/huaweicloud-sdk-go-v3 v0.1.197 -> v0.1.198, tencentcloud-sdk-go v1.3.102 -> v1.3.106, volcengine/volc-sdk-golang v1.0.248 -> v1.0.249

- go-acme/alidns-20150109 major bump v4 -> v5, go-acme/esa-20240910 major bump v2 -> v3 (required by lego v5.2.x directly)

- fsnotify/fsnotify v1.9.0 -> v1.10.1 (also targeted by dependabot PRs #12864 / #12865)

Built and verified on linux/amd64:

  GOOS=linux GOARCH=amd64 CGO_ENABLED=0 go build -trimpath -ldflags='-s -w' ./...

agent and core binaries link cleanly against the upgraded lego and indirect dependencies; no source-level adaptations needed.