Bump Flint version to 0.5.0

[dai-chen]

Description

Bumped Flint version to 0.5.0. Ref: #311

Testing:

$ sbt clean assembly
$ find . -name "*-0.4.0-SNAPSHOT.jar"

$ find . -name "*-0.5.0-SNAPSHOT.jar"
./integ-test/target/scala-2.12/integ-test-assembly-0.5.0-SNAPSHOT.jar
./spark-sql-application/target/scala-2.12/sql-job-assembly-0.5.0-SNAPSHOT.jar
./flint-spark-integration/target/scala-2.12/flint-spark-integration-assembly-0.5.0-SNAPSHOT.jar
./ppl-spark-integration/target/scala-2.12/ppl-spark-integration-assembly-0.5.0-SNAPSHOT.jar

Issues Resolved

N/A

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