chore: os.SEEK_CUR has been deprecated since Go 1.7

[testwill]

• [ ] I updated the documentation explaining the new behavior if any.
• [ ] I updated CHANGELOG.md file adding the new feature or bug fix.
• [ ] I updated go-mysql-server using make upgrade command if applicable.
• [ ] I added or updated examples if applicable.
• [ ] I checked that changes on schema are reflected into the documentation, if applicable.