Use standard User-Agent header instead of X-UC-User-Agent

X-UC-User-Agent is a CORS-allowed custom header designed for the
JavaScript upload widget running in browsers, where overriding the
browser's built-in User-Agent is restricted. Server-side SDKs have
no such restriction. All other Uploadcare server-side SDKs (Python,
PHP, Ruby, Java) use the standard User-Agent header. The Go SDK
adopted X-UC-User-Agent in 2019 without clear justification.

Author: alxgsv

ucare/config.go

@@ -20,7 +20,7 @@ var (
 	defaultAPIVersion = APIv07
 
 	authHeaderKey      = http.CanonicalHeaderKey("Authorization")
-	userAgentHeaderKey = http.CanonicalHeaderKey("X-UC-User-Agent")
+	userAgentHeaderKey = http.CanonicalHeaderKey("User-Agent")
 
 	dateHeaderLocation = time.FixedZone("GMT", 0)
 )

ucare/restapi_test.go

@@ -57,8 +57,8 @@ func TestRESTAPIClient(t *testing.T) {
 				"application/vnd.uploadcare-v0.7+json" {
 				return errors.New("wrong accept header")
 			}
-			if h.Get("X-UC-User-Agent") !=
-				"UploadcareGo/0.2.0/testpublickey" {
+			if h.Get("User-Agent") !=
+				"UploadcareGo/2.0.0/testpublickey" {
 				return errors.New("wrong user-agent header")
 			}
 			if h.Get("Content-Type") != "application/json" {