Release v6.12.3

• [fix] Set payment days considering joinging date, reliving date and applicable holidays
• [fix] Payment Days and holidays considering joining and relieving dates
• [fix] Toggle required for sales and purchase tax template based on tax type
• [minor] allow stock entry for manufacture without production order
• [minor] validate email id before inviting user
• [minor] fixes to patch
• Balance in chart of accounts in both company and account currency
• [fix] Don't overwrite exchange rate on saving for bank transfer