Bump testng from 6.9.10 to 7.7.0 in /flink/flink-twitter-collection

Bumps [testng](https://github.com/cbeust/testng) from 6.9.10 to 7.7.0.
- [Release notes](https://github.com/cbeust/testng/releases)
- [Changelog](https://github.com/cbeust/testng/blob/master/CHANGES.txt)
- [Commits](https://github.com/cbeust/testng/compare/6.9.10...7.7.0)

---
updated-dependencies:
- dependency-name: org.testng:testng
  dependency-type: direct:development
...

Signed-off-by: dependabot[bot] <support@github.com>
diff --git a/flink/flink-twitter-collection/pom.xml b/flink/flink-twitter-collection/pom.xml
index 0031724..c6f3cb6 100644
--- a/flink/flink-twitter-collection/pom.xml
+++ b/flink/flink-twitter-collection/pom.xml
@@ -32,7 +32,7 @@
     <description>Collects twitter documents using flink.</description>
 
     <properties>
-        <testng.version>6.9.10</testng.version>
+        <testng.version>7.7.0</testng.version>
         <hdfs.version>2.7.0</hdfs.version>
         <flink.version>1.2.0</flink.version>
         <scala.version>2.10.6</scala.version>