fix: Fix dockerfile and docker-compose for testing suite (#239)

- This was broken after the postgresql-partman update: https://github.com/dbsystel/postgresql-partman-container/pull/32
- Also needed to specify proper env variables

Co-authored-by: TAMARA LIPOWSKI <data.lipowski@extaccount.com>

testing/docker-compose.yaml

@@ -6,12 +6,14 @@ services:
       dockerfile: postgres.Dockerfile
     restart: "always"
     environment:
-      POSTGRESQL_PASSWORD: mypassword
-      POSTGRESQL_DATABASE: tycho_indexer_0
-      POSTGRESQL_USERNAME: postgres
+      POSTGRES_PASSWORD: mypassword
+      POSTGRES_DATABASE: tycho_indexer_0
+      POSTGRES_USERNAME: postgres
       POSTGRESQL_SHARED_PRELOAD_LIBRARIES: pg_cron
     ports:
       - "5431:5432"
     shm_size: "1gb"
+    volumes:
+      - postgres_data:/var/lib/postgresql/data
 volumes:
-  postgres_data:
+  postgres_data: