Sanitize all SQL query fields from PostgreSQL logs

This upgrades fluent-plugin-postgresql-csvlog to v0.2.1, which normalizes SQL logs from both slow logs and statement cancellations (gitlab-org/fluent-plugins/fluent-plugin-postgresql-csvlog!8 (merged)).

Sample output for a cancellation log message:

{
  "time": "2021-03-21T13:38:13.719Z",
  "user_name": "gitlab",
  "database_name": "gitlabhq_production",
  "process_id": "63054",
  "connection_from": "127.0.0.1:49126",
  "session_id": "6057480b.f64e",
  "session_line_num": "12",
  "command_tag": "SELECT",
  "session_start_time": "2021-03-21 13:20:11 GMT",
  "virtual_transaction_id": "31/106836316",
  "transaction_id": "0",
  "error_severity": "ERROR",
  "sql_state_code": "57014",
  "message": "canceling statement due to statement timeout",
  "detail": null,
  "hint": null,
  "internal_query": null,
  "internal_query_pos": null,
  "context": null,
  "query_pos": null,
  "location": null,
  "application_name": "",
  "fingerprint": "9b4f461e2c9c8c2d",
  "sql": "SELECT COUNT(*) FROM (SELECT $1 AS one FROM \"notes\" WHERE \"notes\".\"project_id\" = $2 AND \"notes\".\"noteable_type\" = $3 AND \"notes\".\"noteable_id\" IN (SELECT \"issues\".\"id\" FROM \"issues\" WHERE (issues.confidential IS NOT TRUE) AND \"issues\".\"project_id\" = $4) AND \"notes\".\"note\" ILIKE $5 AND \"notes\".\"system\" = $6 ORDER BY \"notes\".\"created_at\" ASC, \"notes\".\"id\" ASC, updated_at DESC LIMIT $7) subquery_for_count",
  "application": "web",
  "controller": "search",
  "action": "count",
  "correlation_id": "01F1AG3DCX4PPZ5A73D6RECM2H",
  "endpoint_id": "SearchController#count",
  "tag": "postgres.postgres_csv",
  "environment": "gprd",
  "hostname": "patroni-02-db-gprd",
  "fqdn": "patroni-02-db-gprd.c.gitlab-production.internal",
  "stage": "main",
  "shard": "default",
  "tier": "db",
  "type": "patroni"
}