Fix: outdated Dockerfile syntax

Author: xsedla1o

docker/python/Dockerfile

@@ -1,7 +1,7 @@
 # syntax=docker/dockerfile:1
 
 # Base interpreter with installed requirements
-FROM python:3.9-slim as base
+FROM python:3.9-slim AS base
 RUN apt-get update; apt-get install -y  \
     gcc \
     git

docker/rabbitmq/Dockerfile

@@ -2,7 +2,7 @@
 FROM rabbitmq:3-management
 
 # Define environment variable indicating file in which the process id is placed for use by `rabbitmqctl wait`
-ENV RABBITMQ_PID_FILE /var/lib/rabbitmq/mnesia/rabbitmq
+ENV RABBITMQ_PID_FILE=/var/lib/rabbitmq/mnesia/rabbitmq
 
 # Add custom configuration script
 ADD init-rmq.sh /init-rmq.sh