fix: Taxjar minor fixes
diff --git a/erpnext/erpnext_integrations/taxjar_integration.py b/erpnext/erpnext_integrations/taxjar_integration.py
index a4e2157..14c86d5 100644
--- a/erpnext/erpnext_integrations/taxjar_integration.py
+++ b/erpnext/erpnext_integrations/taxjar_integration.py
@@ -8,10 +8,6 @@
 
 from erpnext import get_default_company, get_region
 
-TAX_ACCOUNT_HEAD = frappe.db.get_single_value("TaxJar Settings", "tax_account_head")
-SHIP_ACCOUNT_HEAD = frappe.db.get_single_value("TaxJar Settings", "shipping_account_head")
-TAXJAR_CREATE_TRANSACTIONS = frappe.db.get_single_value("TaxJar Settings", "taxjar_create_transactions")
-TAXJAR_CALCULATE_TAX = frappe.db.get_single_value("TaxJar Settings", "taxjar_calculate_tax")
 SUPPORTED_COUNTRY_CODES = ["AT", "AU", "BE", "BG", "CA", "CY", "CZ", "DE", "DK", "EE", "ES", "FI",
 	"FR", "GB", "GR", "HR", "HU", "IE", "IT", "LT", "LU", "LV", "MT", "NL", "PL", "PT", "RO",
 	"SE", "SI", "SK", "US"]
@@ -35,12 +31,14 @@
 	if api_key and api_url:
 		client = taxjar.Client(api_key=api_key, api_url=api_url)
 		client.set_api_config('headers', {
-				'x-api-version': '2020-08-07'
+				'x-api-version': '2022-01-24'
 			})
 		return client
 
 
 def create_transaction(doc, method):
+	TAXJAR_CREATE_TRANSACTIONS = frappe.db.get_single_value("TaxJar Settings", "taxjar_create_transactions")
+
 	"""Create an order transaction in TaxJar"""
 
 	if not TAXJAR_CREATE_TRANSACTIONS:
@@ -51,6 +49,7 @@
 	if not client:
 		return
 
+	TAX_ACCOUNT_HEAD = frappe.db.get_single_value("TaxJar Settings", "tax_account_head")
 	sales_tax = sum([tax.tax_amount for tax in doc.taxes if tax.account_head == TAX_ACCOUNT_HEAD])
 
 	if not sales_tax:
@@ -79,6 +78,7 @@
 
 def delete_transaction(doc, method):
 	"""Delete an existing TaxJar order transaction"""
+	TAXJAR_CREATE_TRANSACTIONS = frappe.db.get_single_value("TaxJar Settings", "taxjar_create_transactions")
 
 	if not TAXJAR_CREATE_TRANSACTIONS:
 		return
@@ -92,6 +92,8 @@
 
 
 def get_tax_data(doc):
+	SHIP_ACCOUNT_HEAD = frappe.db.get_single_value("TaxJar Settings", "shipping_account_head")
+
 	from_address = get_company_address_details(doc)
 	from_shipping_state = from_address.get("state")
 	from_country_code = frappe.db.get_value("Country", from_address.country, "code")
@@ -113,20 +115,20 @@
 		to_shipping_state = get_state_code(to_address, 'Shipping')
 
 	tax_dict = {
-		'from_country': from_country_code,
-		'from_zip': from_address.pincode,
-		'from_state': from_shipping_state,
-		'from_city': from_address.city,
-		'from_street': from_address.address_line1,
-		'to_country': to_country_code,
-		'to_zip': to_address.pincode,
-		'to_city': to_address.city,
-		'to_street': to_address.address_line1,
-		'to_state': to_shipping_state,
-		'shipping': shipping,
-		'amount': doc.net_total,
-		'plugin': 'erpnext',
-		'line_items': line_items
+		"from_country": from_country_code,
+		"from_zip": from_address.pincode,
+		"from_state": from_shipping_state,
+		"from_city": from_address.city,
+		"from_street": from_address.address_line1,
+		"to_country": to_country_code,
+		"to_zip": to_address.pincode,
+		"to_city": to_address.city,
+		"to_street": to_address.address_line1,
+		"to_state": to_shipping_state,
+		"shipping": shipping,
+		"amount": doc.net_total,
+		"plugin": "erpnext",
+		"line_items": line_items
 	}
 	return tax_dict
 
@@ -156,6 +158,9 @@
 	return tax_dict
 
 def set_sales_tax(doc, method):
+	TAX_ACCOUNT_HEAD = frappe.db.get_single_value("TaxJar Settings", "tax_account_head")
+	TAXJAR_CALCULATE_TAX = frappe.db.get_single_value("TaxJar Settings", "taxjar_calculate_tax")
+
 	if not TAXJAR_CALCULATE_TAX:
 		return
 
@@ -206,6 +211,7 @@
 			doc.run_method("calculate_taxes_and_totals")
 
 def check_for_nexus(doc, tax_dict):
+	TAX_ACCOUNT_HEAD = frappe.db.get_single_value("TaxJar Settings", "tax_account_head")
 	if not frappe.db.get_value('TaxJar Nexus', {'region_code': tax_dict["to_state"]}):
 		for item in doc.get("items"):
 			item.tax_collectable = flt(0)
@@ -218,6 +224,8 @@
 
 def check_sales_tax_exemption(doc):
 	# if the party is exempt from sales tax, then set all tax account heads to zero
+	TAX_ACCOUNT_HEAD = frappe.db.get_single_value("TaxJar Settings", "tax_account_head")
+
 	sales_tax_exempted = hasattr(doc, "exempt_from_sales_tax") and doc.exempt_from_sales_tax \
 		or frappe.db.has_column("Customer", "exempt_from_sales_tax") \
 		and frappe.db.get_value("Customer", doc.customer, "exempt_from_sales_tax")