Fix CI workflow: Use ../mvnw for assembly generation in spring-ai-docs (spring-projects#4072)

The CI was failing because the 'Generate assembly' step was trying to run
./mvnw from within the spring-ai-docs directory, but the Maven wrapper
script only exists in the repository root.

Fixed by changing './mvnw' to '../mvnw' to reference the script from
the parent directory while maintaining the correct working directory
for the assembly generation.

Fixes the error: ./mvnw: No such file or directory

Author: markpollack

.github/workflows/continuous-integration.yml

@@ -62,7 +62,7 @@ jobs:
 
       - name: Generate assembly
         working-directory: spring-ai-docs
-        run: ./mvnw --batch-mode assembly:single
+        run: ../mvnw --batch-mode assembly:single
 
       - name: Capture project version
         run: echo PROJECT_VERSION=$(mvn help:evaluate -Dexpression=project.version --quiet -DforceStdout) >> $GITHUB_ENV