main/fortify-headers: build from snapshot

upstream switched to a git host which doesn't provide tarballs.
Unfortunately, `abuild snapshot` enforces a change of the version
scheme.

Fixes #12108
7 jobs for !16095 with fortify-source-snapshot in 1 minute and 20 seconds (queued for 1 second)
detached
Status Job ID Name Coverage
  Lint
failed #279185
docker-alpine x86_64 allowed to fail
lint

00:00:22

 
  Build
failed #279190
docker-alpine ci-build aarch64
build-aarch64

00:00:31

failed #279191
docker-alpine ci-build armv7
build-armv7

00:00:35

failed #279189
docker-alpine ci-build ppc64le
build-ppc64le

00:00:55

failed #279188
docker-alpine ci-build s390x
build-s390x

00:00:46

failed #279187
docker-alpine ci-build x86
build-x86

00:00:23

failed #279186
docker-alpine ci-build x86_64
build-x86_64

00:00:30

 
Name Stage Failure
failed
build-x86_64 Build
No job log
failed
lint Lint
No job log
failed
build-aarch64 Build
No job log
failed
build-armv7 Build
No job log
failed
build-x86 Build
No job log
failed
build-s390x Build
No job log
failed
build-ppc64le Build
No job log