Update gitea go-sdk to v0.15.0 (#385)

Update "code.gitea.io/sdk/gitea" to latest release

Reviewed-on: https://gitea.com/gitea/tea/pulls/385
Reviewed-by: Lunny Xiao <xiaolunwen@gmail.com>
Reviewed-by: Andrew Thornton <art27@cantab.net>
Co-authored-by: 6543 <6543@obermui.de>
Co-committed-by: 6543 <6543@obermui.de>

vendor/code.gitea.io/sdk/gitea/git_blob.go

@@ -19,6 +19,9 @@ type GitBlobResponse struct {
 
 // GetBlob get the blob of a repository file
 func (c *Client) GetBlob(user, repo, sha string) (*GitBlobResponse, *Response, error) {
+	if err := escapeValidatePathSegments(&user, &repo, &sha); err != nil {
+		return nil, nil, err
+	}
 	blob := new(GitBlobResponse)
 	resp, err := c.getParsedResponse("GET", fmt.Sprintf("/repos/%s/%s/git/blobs/%s", user, repo, sha), nil, nil, blob)
 	return blob, resp, err