Fix invalid lambda example

[khanhtc1202]

What this PR does / why we need it:

Suspends this error

failed to read unregistered application info {"repo-id": "examples", "config-file-path": "lambda/analysis/app.pipecd.yaml", "error": "failed to decode configuration file: the ANALYSIS stage requires duration field"}

Which issue(s) this PR fixes:

Fixes #

Does this PR introduce a user-facing change?:

NONE

[pipecd-bot]

Code coverage for golang is 35.62%. This pull request does not change code coverage.

[nghialv]

Nice catch!
/approve

[pipecd-bot]

This pull request is APPROVED by nghialv.

Approvers can cancel the approval by writing /approve cancel in a comment. Any additional commits also will change this pull request to be not-approved.