fix: Update to Java 11, since runtime doesn't support 8. (#1867)

The CI was unable to run because class files required version 11 of Java.

.github/workflows/samples.yaml

@@ -24,7 +24,7 @@ jobs:
       - uses: actions/setup-java@v4
         with:
           distribution: temurin
-          java-version: 8
+          java-version: 11
       - name: Run checkstyle
         run: mvn -P lint --quiet --batch-mode checkstyle:check
         working-directory: samples/snippets

README.md

@@ -19,7 +19,7 @@ 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>26.47.0</version>
+      <version>26.48.0</version>
       <type>pom</type>
       <scope>import</scope>
     </dependency>
@@ -42,7 +42,7 @@ If you are using Maven without the BOM, add this to your dependencies:
 <dependency>
   <groupId>com.google.cloud</groupId>
   <artifactId>google-cloud-firestore</artifactId>
-  <version>3.26.5</version>
+  <version>3.27.0</version>
 </dependency>
 
 ```