Add the BUILD.bazel file to the wasm_bindgen distro filegroup target (#1246) (#1261)

diff --git a/wasm_bindgen/BUILD.bazel b/wasm_bindgen/BUILD.bazel
index bf8b589..65b6f74 100644
--- a/wasm_bindgen/BUILD.bazel
+++ b/wasm_bindgen/BUILD.bazel
@@ -14,6 +14,7 @@
 filegroup(
     name = "distro",
     srcs = glob(["*.bzl"]) + [
+        "BUILD.bazel",
         "//wasm_bindgen/raze:srcs",
         "//wasm_bindgen/raze/remote:srcs",
     ],