Fix reporting of version in prebuilt binaries & docker image

docker-bake.hcl

@@ -1,3 +1,8 @@
+// This is used to set the version reported by the binary through an environment
+// variable. This is mainly useful when building out of a git context, like in
+// CI, where we don't have the full commit history available
+variable "VERGEN_GIT_DESCRIBE" {}
+
 // This is what is baked by GitHub Actions
 group "default" { targets = ["regular", "debug", "syn2mas"] }
 
@@ -11,8 +16,11 @@ target "docker-metadata-action-syn2mas" {}
 target "base" {
   args = {
     // This is set so that when we use a git context, the .git directory is
-    // present, as we infer the version at build time out of it
+    // present, as we may be infering the version at build time out of it
     BUILDKIT_CONTEXT_KEEP_GIT_DIR = 1
+
+    // Pass down the version from an external git describe source
+    VERGEN_GIT_DESCRIBE = "${VERGEN_GIT_DESCRIBE}"
   }
 
   platforms = [