metropolis: use //version

This switches over the Metropolis codebase from the previous build
stamping system to the new //version library.

Change-Id: I8ecb0c3b4b19098e0026215444bae9b34060440e
Reviewed-on: https://review.monogon.dev/c/monogon/+/2333
Tested-by: Jenkins CI
Reviewed-by: Lorenz Brun <lorenz@monogon.tech>
diff --git a/metropolis/version/BUILD.bazel b/metropolis/version/BUILD.bazel
new file mode 100644
index 0000000..40a0991
--- /dev/null
+++ b/metropolis/version/BUILD.bazel
@@ -0,0 +1,19 @@
+load("@io_bazel_rules_go//go:def.bzl", "go_library")
+load("//version:defs.bzl", "go_version_library")
+
+go_version_library(
+    name = "version_lib",
+    importpath = "source.monogon.dev/metropolis/version",
+    product = "metropolis",
+)
+
+go_library(
+    name = "version",
+    embed = [
+        ":version_lib",  # keep
+    ],
+    importpath = "source.monogon.dev/metropolis/version",  # keep
+    visibility = [
+        "//metropolis:__subpackages__",
+    ],
+)
diff --git a/metropolis/version/gomod-generated-placeholder.go b/metropolis/version/gomod-generated-placeholder.go
new file mode 100644
index 0000000..f37d99d
--- /dev/null
+++ b/metropolis/version/gomod-generated-placeholder.go
@@ -0,0 +1 @@
+package version