Fix env vars are not passed in from docker-compose (#7240)

dolphinscheduler-server/src/main/resources/config/install_config.conf

@@ -76,17 +76,17 @@ apiServerPort="12345"
 # ---------------------------------------------------------
 # The type for the metadata database
 # Supported values: ``postgresql``, ``mysql``.
-DATABASE_TYPE="postgresql"
+DATABASE_TYPE=${DATABASE_TYPE:-"postgresql"}
 
 # Spring datasource url, following <HOST>:<PORT>/<database>?<parameter> format, If you using mysql, you could use jdbc
 # string jdbc:mysql://127.0.0.1:3306/dolphinscheduler?useUnicode=true&characterEncoding=UTF-8 as example
-SPRING_DATASOURCE_URL="jdbc:postgresql://127.0.0.1:5432/dolphinscheduler"
+SPRING_DATASOURCE_URL=${SPRING_DATASOURCE_URL:-"jdbc:postgresql://127.0.0.1:5432/dolphinscheduler"}
 
 # Spring datasource username
-SPRING_DATASOURCE_USERNAME="ds_user"
+SPRING_DATASOURCE_USERNAME=${SPRING_DATASOURCE_USERNAME:-"ds_user"}
 
 # Spring datasource password
-SPRING_DATASOURCE_PASSWORD="dolphinscheduler"
+SPRING_DATASOURCE_PASSWORD=${SPRING_DATASOURCE_PASSWORD:-"dolphinscheduler"}
 
 # ---------------------------------------------------------
 # Registry Server