Timestamp the static manifest's licences

Signed-off-by: Maartje Eyskens <maartje@eyskens.me>

build/licensing.bzl

@@ -19,7 +19,7 @@ def licensed_file(
     # This uses '#' as a way to denote a comment.
     # This will likely need changing depending on the type of the file being
     # generated.
-    license_boilerplate = "//hack/boilerplate:boilerplate.bzl.txt",
+    license_boilerplate = "//hack/boilerplate:boilerplate.bzl.timestamped.txt",
     **kwargs,
 ):
     native.genrule(

hack/boilerplate/BUILD.bazel

@@ -13,3 +13,16 @@ filegroup(
     tags = ["automanaged"],
     visibility = ["//visibility:public"],
 )
+
+genrule(
+    name = "boilerplate.bzl.timestamped.txt",
+    srcs = [":boilerplate.bzl.txt"],
+    outs = ["boilerplate.bzl.timestamped.txt.out"],
+    cmd = " ".join([
+        "sed",
+        "s/YEAR/$$(date +\"%Y\")/",
+        "$(location :boilerplate.bzl.txt)",
+        "> $@",
+    ]),
+    visibility = ["//visibility:public"],
+)