feat: add libraries_bom_version in metadata (#1956)

* feat: add libraries_bom_version

* add unit tests

* remove isfile

* add tempdir

* restore

* add current dir

* restore template

* remove unit test

* restore templates
Source-Link: googleapis/synthtool@63cc541
Post-Processor: gcr.io/cloud-devrel-public-resources/owlbot-java:latest@sha256:dc11e2119c854b57b7f7ed9962391decf002454700020a52b5d0d46c40b80a7e

.github/.OwlBot.lock.yaml

@@ -1,4 +1,4 @@
-# Copyright 2023 Google LLC
+# Copyright 2024 Google LLC
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.
@@ -13,5 +13,5 @@
 # limitations under the License.
 docker:
   image: gcr.io/cloud-devrel-public-resources/owlbot-java:latest
-  digest: sha256:3a95f1b9b1102865ca551b76be51d2bdb850900c4db2f6d79269e7af81ac8f84
-# created: 2023-07-27T18:37:44.251188775Z
+  digest: sha256:dc11e2119c854b57b7f7ed9962391decf002454700020a52b5d0d46c40b80a7e
+# created: 2024-04-15T22:37:28.944513098Z