ci(Mergify): configuration update

[ankush]

• Auto close PRs on stable branch
• Also use old labels for backporting (for backward compatibility with previous github action)

[codecov]

Codecov Report

Merging #27777 (ec09823) into develop (09ccdee) will decrease coverage by 0.02%.
The diff coverage is n/a.

@@             Coverage Diff             @@
##           develop   #27777      +/-   ##
===========================================
- Coverage    54.47%   54.44%   -0.03%     
===========================================
  Files         1248     1248              
  Lines        67518    67518              
===========================================
- Hits         36781    36762      -19     
- Misses       30737    30756      +19     

Impacted Files	Coverage Δ
...tch_item_expiry_status/batch_item_expiry_status.py	69.81% <0.00%> (-24.53%)	⬇️
erpnext/stock/report/stock_ledger/stock_ledger.py	77.50% <0.00%> (-3.34%)	⬇️
erpnext/education/doctype/student/student.py	74.46% <0.00%> (-3.20%)	⬇️
erpnext/stock/report/stock_ageing/stock_ageing.py	89.20% <0.00%> (-2.16%)	⬇️
...ion/doctype/course_enrollment/course_enrollment.py	45.09% <0.00%> (-1.97%)	⬇️
...eorder_level/itemwise_recommended_reorder_level.py	92.45% <0.00%> (-1.89%)	⬇️
...ctype/accounting_dimension/accounting_dimension.py	64.34% <0.00%> (-1.56%)	⬇️
...e/period_closing_voucher/period_closing_voucher.py	88.23% <0.00%> (-1.48%)	⬇️
erpnext/selling/doctype/sales_order/sales_order.py	76.85% <0.00%> (-0.38%)	⬇️
...stock/doctype/purchase_receipt/purchase_receipt.py	90.34% <0.00%> (-0.27%)	⬇️
... and 7 more