chore: upgrade to robotframework 6.0.1 and install firefox

Dockerfile

@@ -15,13 +15,13 @@ LABEL description="Base image for running Robot Framework test suites in Docker.
     - PyMySQL - Python driver for MySQL"
 
 RUN apt-get update && \
-        apt-get -y install jq && \
+        apt-get -y install jq firefox-esr && \
         rm -r /var/lib/apt/lists/* && \
         pip install \
         urllib3 \
         psycopg2-binary \
         PyMySQL \
-        robotframework==3.2 \
+        robotframework==6.0.1 \
         robotframework-appiumlibrary \
         robotframework-databaselibrary \
         robotframework-httplibrary \