Security update for go1.26

This update for go1.26 fixes the following issues Update to go1.26.4 bsc1255111: CVE-2026-27145: crypto/x509: split candidate hostname only once bsc1267450. CVE-2026-42504: mime: quadratic complexity in WordDecoder.DecodeHeader bsc1267442. CVE-2026-42507: net/textproto: arbitrary input are includ...