chore(deps): update dependency opencensus-ext-flask to v0.7.4 (#5241)
chore(deps): update dependency opencensus-ext-flask to v0.7.4 (#5241)


GoogleCloudPlatform/python-docs-samples,GoogleCloudPlatform/python-docs-samples,GoogleCloudPlatform/python-docs-samples,GoogleCloudPlatform/python-docs-samples