feat: added ocpp 2.1 to docker test

Author: xBlaz3kx

docker-compose.test.yaml

@@ -19,8 +19,10 @@ services:
         go test -v -covermode=count -coverprofile=coverage.out ./ocppj
         go test -v -covermode=count -coverprofile=ocpp16.out -coverpkg=github.com/lorenzodonini/ocpp-go/ocpp1.6/... github.com/lorenzodonini/ocpp-go/ocpp1.6_test
         go test -v -covermode=count -coverprofile=ocpp201.out -coverpkg=github.com/lorenzodonini/ocpp-go/ocpp2.0.1/... github.com/lorenzodonini/ocpp-go/ocpp2.0.1_test
+        go test -v -covermode=count -coverprofile=ocpp21.out -coverpkg=github.com/lorenzodonini/ocpp-go/ocpp2.1/... github.com/lorenzodonini/ocpp-go/ocpp2.1_test
         sed '1d;$d' ocpp16.out >> coverage.out
         sed '1d;$d' ocpp201.out >> coverage.out
+        sed '1d;$d' ocpp21.out >> coverage.out
 
   integration_test:
     image: cimg/go:1.22.5