fix(java-tests): align docs java-v6 client to weaviate client6 6.2.1

The java-v6 examples module depended on client6:6.2.1-SNAPSHOT (which no
release publishes, and the pom has no snapshot repository), while docs CI
built and installed client tag 6.2.0. That version lacks text2vecDigitalOcean
and the tokenize APIs, so ModelProvidersTest and TokenizationTest failed to
compile — breaking the whole module, including the new server-side batching
test. Pin both the dependency and the CI-built client to the released 6.2.1.

Author: g-despot

.github/workflows/docs_tests.yml

@@ -456,7 +456,7 @@ jobs:
 
       - name: Clone and build Java client SNAPSHOT
         run: |
-          JAVA_BRANCH="${{ inputs.java_client_branch || '6.2.0' }}"
+          JAVA_BRANCH="${{ inputs.java_client_branch || '6.2.1' }}"
           echo "📦 Building Java client SNAPSHOT from branch: $JAVA_BRANCH"
           git clone --depth 1 -b "$JAVA_BRANCH" https://github.com/weaviate/java-client.git /tmp/java-client
           cd /tmp/java-client

_includes/code/java-v6/pom.xml

@@ -30,7 +30,7 @@
     <dependency>
       <groupId>io.weaviate</groupId>
       <artifactId>client6</artifactId>
-      <version>6.2.1-SNAPSHOT</version>
+      <version>6.2.1</version>
     </dependency>
 
     <!-- JUnit 5 for testing -->