[GHSA-cvhv-g4rq-3hmw] Add upstream fix commit reference

[Junaid-PK]

Updates

• References

Comments
Adds the upstream ImageMagick fix commit as a public reference.

Evidence:

• The published advisory identifies ImageMagick 7.1.2-27 as the first patched version: GHSA-cvhv-g4rq-3hmw
• The upstream commit message directly names this GHSA and its changes repair the documented CLI memory leaks: ImageMagick/ImageMagick@e3e6911
• That commit is contained in the 7.1.2-27 tag.
• The advisory record already references the corresponding Magick.NET 14.15.0 release.

No affected ranges or other advisory metadata are changed.