Bump pyyaml from 5.1 to 5.4 in /cd/utils

Bumps [pyyaml](https://github.com/yaml/pyyaml) from 5.1 to 5.4.
- [Release notes](https://github.com/yaml/pyyaml/releases)
- [Changelog](https://github.com/yaml/pyyaml/blob/master/CHANGES)
- [Commits](yaml/pyyaml@5.1...5.4)

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

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

Author: dependabot[bot]

cd/utils/requirements.txt

@@ -15,4 +15,4 @@
 # specific language governing permissions and limitations
 # under the License.
 boto3==1.9.114
-PyYAML==5.1
+PyYAML==5.4