fix: allow gen to work with default graphql file and url

Makefile

@@ -1,8 +1,11 @@
 PROVIDER_BIN:=$(shell basename `git rev-parse --show-toplevel`)
 PROVIDER_NAME:=$(shell echo $(PROVIDER_BIN) | sed 's/terraform-provider-//g')
 PROVIDER_DIRECTORY:=~/.terraform.d/plugins/local/altinity/${PROVIDER_NAME}
-GRAPHQL_SCHEMA_URL?=https://anywhere.altinity.cloud/api/v1/graphql.schema
-GRAPHQL_SCHEMA_FILE:=internal/sdk/client/graphql.schema
+DEFAULT_GRAPHQL_SCHEMA_FILE:=internal/sdk/client/graphql.schema
+DEFAULT_GRAPHQL_SCHEMA_URL:=https://anywhere.altinity.cloud/api/v1/graphql.schema
+
+GRAPHQL_SCHEMA_URL:=$(or $(GRAPHQL_SCHEMA_URL),$(DEFAULT_GRAPHQL_SCHEMA_URL))
+GRAPHQL_SCHEMA_FILE:=$(or $(GRAPHQL_SCHEMA_FILE),$(DEFAULT_GRAPHQL_SCHEMA_FILE))
 
 VERSION:=0.0.1
 OS:=darwin
@@ -85,6 +88,7 @@ docs:
 
 .PHONY: sdk
 sdk:
+	@echo "Fetching GraphQL schema from ${GRAPHQL_SCHEMA_URL} to ${GRAPHQL_SCHEMA_FILE}"
 	curl -o ${GRAPHQL_SCHEMA_FILE} ${GRAPHQL_SCHEMA_URL}
 	cd internal/sdk/client && go run github.com/Yamashou/gqlgenc