Bump pyspark from 3.1.2 to 3.1.3 in /examples/spark-app-demo/k8s (#85)

Bumps [pyspark](https://github.com/apache/spark) from 3.1.2 to 3.1.3.
- [Release notes](https://github.com/apache/spark/releases)
- [Commits](https://github.com/apache/spark/compare/v3.1.2...v3.1.3)

---
updated-dependencies:
- dependency-name: pyspark
  dependency-type: direct:production
...

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Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
diff --git a/examples/spark-app-demo/k8s/requirements.txt b/examples/spark-app-demo/k8s/requirements.txt
index db52f8d..fddcc54 100644
--- a/examples/spark-app-demo/k8s/requirements.txt
+++ b/examples/spark-app-demo/k8s/requirements.txt
@@ -18,4 +18,4 @@
 
 scikit-learn==0.24.1
 apache-liminal==0.0.2
-pyspark==3.1.2
+pyspark==3.1.3