chore: Adding release-please annotations to readme files (#1781)

* chore: Adding release-please annotations to readme files
Source-Link: googleapis/synthtool@327d46f
Post-Processor: gcr.io/cloud-devrel-public-resources/owlbot-java:latest@sha256:bf5639d265d70f6137d57d42ae781a6f4e26d4085ff4e018e71350480f9b3996

Author: gcf-owl-bot[bot]

.github/.OwlBot.lock.yaml

@@ -13,4 +13,4 @@
 # limitations under the License.
 docker:
   image: gcr.io/cloud-devrel-public-resources/owlbot-java:latest
-  digest: sha256:381a48baae37646d72557adaa2c2035a84462cfd830269dfb3847b7d7ca9e96d
+  digest: sha256:bf5639d265d70f6137d57d42ae781a6f4e26d4085ff4e018e71350480f9b3996

README.md

@@ -64,6 +64,7 @@ If you are using SBT, add this to your dependencies:
 ```Scala
 libraryDependencies += "com.google.cloud" % "google-cloud-spanner" % "6.38.0"
 ```
+<!-- {x-version-update-end} -->
 
 ## Authentication