Update requirements_test.txt (#748)

* Update requirements_test.txt

fix requirements to exact versions, to improve reproducibility of test flows

* Update requirements_test.txt

* Update requirements_test.txt

bump pytest-homeassistant-custom-component to 0.12.48

Author: lbbrhzn

requirements_test.txt

@@ -1,5 +1,5 @@
 -r requirements_dev.txt
-pytest-homeassistant-custom-component>=0.12.16
-ocpp>=0.15.0
-websockets>=10.4
+pytest-homeassistant-custom-component==0.12.48
+ocpp==0.16.0
+websockets==10.4
 pytest-cov