Bump pyspark from 2.4.4 to 3.2.2 in /requirements

Bumps [pyspark](https://github.com/apache/spark) from 2.4.4 to 3.2.2.
- [Release notes](https://github.com/apache/spark/releases)
- [Commits](https://github.com/apache/spark/compare/v2.4.4...v3.2.2)

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

Signed-off-by: dependabot[bot] <support@github.com>

requirements/build.txt

@@ -21,7 +21,7 @@ pandas==0.23.4
 protobuf==3.13.0
 psycogreen==1.0
 psycopg2-binary==2.7.5
-pyspark==2.4.4
+pyspark==3.2.2
 python-dateutil==2.7.5
 python-jose-cryptodome==1.3.2
 # using git reference as python_moztelemetry