Normalize CLA comment text to handle trailing punctuation

[Copilot]

CLA approvals were failing when users added trailing punctuation to their agreement comment (e.g., "I have hereby read the F5 CLA and agree to its terms."). The workflow used exact string matching which rejected natural variations.

Changes

• Added normalization step that runs on issue_comment events to strip leading/trailing whitespace and trailing punctuation (.!?;,) before matching
• Restructured workflow condition to check pull_request_target events first, then normalized output for issue_comment events (avoids accessing undefined step outputs)
• Secured input handling using environment variables and printf instead of direct interpolation to prevent shell injection
• Updated documentation in README and CHANGELOG to reflect the normalization behavior

Implementation

- name: Normalize comment body
  id: normalize
  if: github.event_name == 'issue_comment'
  env:
    COMMENT_BODY: ${{ github.event.comment.body }}
  run: |
    NORMALIZED=$(printf '%s\n' "$COMMENT_BODY" | sed 's/^[[:space:]]*//; s/[[:space:]]*$//; s/[.!?;,]*$//')
    echo "normalized=$NORMALIZED" >> "$GITHUB_OUTPUT"

- name: Run F5 CLA assistant
  if: |
    github.event_name == 'pull_request_target' ||
    (github.event_name == 'issue_comment' &&
     (steps.normalize.outputs.normalized == 'recheck' ||
      steps.normalize.outputs.normalized == 'I have hereby read the F5 CLA and agree to its terms'))

Backward compatible—comments without punctuation continue to work unchanged.

Original prompt

---

This section details on the original issue you should resolve

<issue_title>CLA approvals fail when users add a period to the end of a sentence</issue_title>
<issue_description>### Bug Overview

Example: nginx/documentation#512

• There was a failure when the PR author signed the CLA, and added a period at the end of the sentence.

Expected Behavior

When the user signs the CLA in a reasonable way, the CLA test accepts it

Steps to Reproduce the Bug

1. New user
2. The user submits a PR
3. The user signs the CLA, and adds a period to the end of the sentence.

Environment Details

GitHub UI

Additional Context

No response</issue_description>

Comments on the Issue (you are @copilot in this section)

@alessfg There is not much we can do about this since from what I can tell, the signature message parameter does not allow a regex. @alessfg The CLA action does not allow multiple answers sadly... We need to figure out if there's a way to do some level of regex handling before the proper CLA action runs.

• Fixes CLA approvals fail when users add a period to the end of a sentence #13

---

✨ Let Copilot coding agent set things up for you — coding agent works faster and does higher quality work when set up for your repo.

[TasoOneAsia]

Logic looked okay aside from one comment.