How to change xml declaration from single quotes to double quotes

Encoding method has single quotes. Needs to be updated to double quotes <?xml version="1.0" encoding="utf-8"?>

Problem Description

Payment files generated have single quotes for encoding method <?xml version='1.0' encoding='utf-8'?>. Bank requires it to be double quotes <?xml version="1.0" encoding="utf-8"?>

Updated the xsl file and removed single quotes encoding but it gets added by default. See below sample of modified xsl:

XSL File:

<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
<xsl:output omit-xml-declaration="no" />
<xsl:output method="xml" />
<xsl:key name="contacts-by-LogicalGroupReference" match="OutboundPayment" use="LogicalGrouping/LogicalGroupReference" />
<xsl:template match="OutboundPaymentInstruction">