chore: regenerate README versions (#233)

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PiperOrigin-RevId: 309824146
Source-Link: googleapis/googleapis@e0f9d9e

Author: yoshi-automation

README.md

@@ -17,7 +17,7 @@ If you are using Maven with [BOM][libraries-bom], add this to your pom.xml file
     <dependency>
       <groupId>com.google.cloud</groupId>
       <artifactId>libraries-bom</artifactId>
-      <version>5.1.0</version>
+      <version>5.4.0</version>
       <type>pom</type>
       <scope>import</scope>
     </dependency>
@@ -38,7 +38,7 @@ If you are using Maven without BOM, add this to your dependencies:
 <dependency>
   <groupId>com.google.cloud</groupId>
   <artifactId>google-cloud-spanner</artifactId>
-  <version>1.52.0</version>
+  <version>1.54.0</version>
 </dependency>
 
 ```

synth.metadata

@@ -4,15 +4,15 @@
       "git": {
         "name": ".",
         "remote": "https://github.com/googleapis/java-spanner.git",
-        "sha": "5806b0e1c7c5bfe7891283ae515b114b3ef814d9"
+        "sha": "be7d713eaa1f7342f43cf6cdc0b08109b69cd4cc"
       }
     },
     {
       "git": {
         "name": "googleapis",
         "remote": "https://github.com/googleapis/googleapis.git",
-        "sha": "ab5d07c2883026eec395d73ff59a17f4ad0153db",
-        "internalRef": "306557455"
+        "sha": "e0f9d9e1f9de890db765be46f45ca8490723e3eb",
+        "internalRef": "309824146"
       }
     },
     {