DB_CONNECTION is incorrect when using platform project:init

[gilzow]

Line 10 of platformifier/templates/generic/.environment has the following:

{{ if eq .Database "postgresql" }}export DB_CONNECTION="postgresql"{{ else }}export DB_CONNECTION="${{ .DatabaseUpper }}_SCHEME"{{ end }}

However, Platform.sh has not implemented expanded environment variables, so the environment variable of <DATABASENAME>_SCHEME does not exist.

In the case of the following example, DB_CONNECTION ends up being empty since MARIADB_SCHEME does not exist:

export RELATIONSHIPS_JSON="$(echo $PLATFORM_RELATIONSHIPS | base64 --decode)"

# Set database environment variables
export DB_HOST="$(echo $RELATIONSHIPS_JSON | jq -r '.mariadb[0].host')"
export DB_PORT="$(echo $RELATIONSHIPS_JSON | jq -r '.mariadb[0].port')"
export DB_DATABASE="$(echo $RELATIONSHIPS_JSON | jq -r '.mariadb[0].path')"
export DB_USERNAME="$(echo $RELATIONSHIPS_JSON | jq -r '.mariadb[0].username')"
export DB_PASSWORD="$(echo $RELATIONSHIPS_JSON | jq -r '.mariadb[0].password')"
export DB_CONNECTION="$MARIADB_SCHEME"
export DATABASE_URL="${DB_CONNECTION}://${DB_USERNAME}:${DB_PASSWORD}@${DB_HOST}:${DB_PORT}/${DB_DATABASE}"