pcloud: only use SHA1 hashes in EU region

Apparently only SHA1 hashes are supported in the EU region for
pcloud. This has been confirmed by pCloud support. The EU regions also
support SHA256 hashes which we don't support yet.

https://forum.rclone.org/t/pcloud-to-local-no-hashes-in-common/19440

backend/pcloud/api/types.go

@@ -104,8 +104,9 @@ type ItemResult struct {
 
 // Hashes contains the supported hashes
 type Hashes struct {
-	SHA1 string `json:"sha1"`
-	MD5  string `json:"md5"`
+	SHA1   string `json:"sha1"`
+	MD5    string `json:"md5"`
+	SHA256 string `json:"sha256"`
 }
 
 // UploadFileResponse is the response from /uploadfile