Fix release workflow: broken regex and fragile multiline handling for bump detection

[Copilot]

Description

Fix release workflow bump detection: correct broken regex (\[xX\] → \[[xX]\]), use temp file + awk markers for reliable multiline PR body handling, replace echo | grep with here-strings, and fall back to full-body scan when markers are missing.

Type of Change

• Major – Breaking change (requires a new major version bump)
• Minor – New feature, backward-compatible (requires a new minor version bump)
• Patch – Bug fix or internal improvement, backward-compatible (requires a new patch version bump)

Details

Release workflow fails to detect checked version-bump checkbox (run #22827290539), even when - [x] **Patch** is clearly present in the PR body.

Broken regex

\[xX\] in ERE matches the literal 4-char string [xX], not [x] or [X]:

# Before — never matches
echo '- [x] **Patch**' | grep -qE '\[xX\] \*\*Patch\*\*'   # NO MATCH

# After — character class works correctly
echo '- [x] **Patch**' | grep -qE '\[[xX]\] \*\*Patch\*\*'  # MATCH

Fragile multiline handling

• PR body is now written to a temp file via printf to reliably preserve newlines regardless of shell behavior
• Checkbox lines are extracted between <!--changelog-type-start--> / <!--changelog-type-end--> markers with awk before grepping, avoiding false matches from other sections
• When markers are missing (e.g., PR not created from the template), the workflow falls back to scanning the full PR body with a ::warning:: annotation instead of failing with a misleading error

Robust grep usage

• Replaced echo "$VAR" | grep with here-strings (grep ... <<< "$VAR") to avoid echo's implementation-defined behavior with certain leading characters and escape sequences

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[Copilot]

Pull request overview

This PR updates the release GitHub Actions workflow to correctly detect the selected version-bump checkbox in merged PR bodies, making bump detection more reliable for multiline PR descriptions.

Changes:

• Fix the checkbox-regex so [x] / [X] are matched correctly in ERE.
• Persist the PR body to a temp file and write it to GITHUB_OUTPUT via cat to preserve multiline content.
• Restrict bump detection to the section between <!--changelog-type-start--> and <!--changelog-type-end--> markers.

[nilsandrey]

@copilot Update this PR description to have the expected sections for the Release pipeline used to update changelog and release I think.

Description

Type of Change

• Major – Breaking change (requires a new major version bump)
• Minor – New feature, backward-compatible (requires a new minor version bump)
• Patch – Bug fix or internal improvement, backward-compatible (requires a new patch version bump)

[Copilot]

@copilot Update this PR description to have the expected sections for the Release pipeline used to update changelog and release I think.

Description

...

Updated the PR description with the expected ## Description (wrapped in <!--changelog-description-start--> / <!--changelog-description-end--> markers) and ## Type of Change sections (with <!--changelog-type-start--> / <!--changelog-type-end--> markers and Patch checked).