Bump pyyaml from 5.3.1 to 5.4 in /sparkler-sce/webui (#226)

Bumps [pyyaml](https://github.com/yaml/pyyaml) from 5.3.1 to 5.4.
- [Release notes](https://github.com/yaml/pyyaml/releases)
- [Changelog](https://github.com/yaml/pyyaml/blob/master/CHANGES)
- [Commits](yaml/pyyaml@5.3.1...5.4)

Signed-off-by: dependabot[bot] <[email protected]>

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

sparkler-sce/webui/requirements.txt

@@ -26,7 +26,7 @@ pyArango==1.3.4
 pylint==2.4.4
 pyrsistent==0.16.0
 pytz==2019.3
-PyYAML==5.3.1
+PyYAML==5.4
 requests==2.23.0
 scikit-learn==0.22.2.post1
 scipy==1.4.1