deps: update dependency hashicorp/packer to v1.15.1

[renovate]

This PR contains the following updates:

Package	Update	Change
hashicorp/packer	patch	1.15.0 → 1.15.1

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Release Notes

hashicorp/packer (hashicorp/packer)

v1.15.1

Compare Source

FEATURES:

• hcp: native sbom generation for hcp
  GH-13566

BUG FIXES:

• core: Scrub multiline sensitive values from build output (including OS-specific multiline sensitive-value fixtures)
  GH-13582

SECURITY:

• deps: bump syft to v1.42.3 (fixes GO-2026-4809)
  GH-13581
• deps: bump github.com/hashicorp/packer-plugin-sdk to v0.6.7
  GH-13581
• deps: bump github.com/hashicorp/hcp-sdk-go from 0.136.0 to 0.167.0
  GH-13560
• deps: Updates OpenTelemetry dependencies to v1.41.0
  GH-13572
• deps: Upgrade go-git to v5.17.0 and grpc to 1.79.3
  GH-13570
• deps: Updates circl dependency to v1.6.3
  GH-13564

INTERNAL:

• ci: Adds grouped and scheduled updates for GitHub Actions (monthly, grouped PRs, ignore major bumps)
  GH-13575
• docs: remove docs validation from packer (docs changes move to web-unified-docs)
  GH-13577
• legal: Update LICENSE
  GH-13563

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