Update EditPullRequestOption Add Base (#353)

Follow go-gitea/gitea#11666

Reviewed-on: https://gitea.com/gitea/go-sdk/pulls/353
Reviewed-by: 6543 <[email protected]>
Reviewed-by: John Olheiser <[email protected]>

Author: blaggacao

gitea/pull.go

@@ -139,6 +139,7 @@ func (c *Client) CreatePullRequest(owner, repo string, opt CreatePullRequestOpti
 type EditPullRequestOption struct {
 	Title     string     `json:"title"`
 	Body      string     `json:"body"`
+	Base      string     `json:"base"`
 	Assignee  string     `json:"assignee"`
 	Assignees []string   `json:"assignees"`
 	Milestone int64      `json:"milestone"`