chore: bump pg-actions sbom.yml to 218190a (main)

[pgmac]

Bumps pgmac-net/pg-actions/.github/workflows/sbom.yml pin to 218190a (main).

Picks up:

• fix: replace DependencyTrack/gh-upload-sbom node20 action with curl (#80)
• fix: avoid ARG_MAX limit when uploading large SBoMs to DTrack (#81)
• fix: use mise install script instead of GitHub releases download (#79)
• fix: switch gh and syft from aqua to github backend (#78)

🤖 Generated with Claude Code

[github-actions]

Docker Build

Field	Value
Status	Built (not pushed -- PR build only)
Tag	pr-17-a09b3ad
Commit	a09b3ad

Image will be pushed to macro.int.pgmac.net:5000 on merge to master.
This comment is updated on each commit.