Add qiskit-device-benchmarking to requirements.txt (#5599)

The refresh-backend-properties-with-real-time-benchmarking tutorial
requires qiskit-device-benchmarking as a dependency
([link](https://quantum.cloud.ibm.com/docs/en/tutorials/refresh-backend-properties-with-real-time-benchmarking#requirements)).
This PR adds that dependency to requirements.txt.


[aff6064fe5079df572b807b1ee5c9e06ea74fa13](qiskit-community/qiskit-device-benchmarking@aff6064)
is the latest commit from the repo on the `main` branch as of this PR.

Author: emilkovacev

scripts/nb-tester/requirements.txt

@@ -32,3 +32,4 @@ qiskit_addon_slc~=0.1.0
 mthree~=3.0.0
 qctrl-visualizer~=11.0.0
 imbalanced-learn~=0.14.2
+qiskit-device-benchmarking @ git+https://github.com/qiskit-community/qiskit-device-benchmarking.git@aff6064fe5079df572b807b1ee5c9e06ea74fa13