retention is mandatory param at LogGroups

Fail with error `Missing required key 'retentionInDays' in params`
```ts
new c3.logs.LogGroup(stack, 'MyLogs', {
  kmsKey,
  logGroupName: 'MyLogs',
  removalPolicy,
})
```

Ok:
```ts
new c3.logs.LogGroup(stack, 'MyLogs', {
  kmsKey,
  logGroupName: 'MyLogs',
  removalPolicy,
  retention: logs.RetentionDays.ONE_DAY,
})
```

