more useful output for update_fake_backends.py

[1ucian0]

This PR extends tools/update_fake_backends.py to warning the user when the snapshot has errors of 1.

@nonhermitian noticed that some calibration data was bad when I was creating FakeGeneva in https://github.com/Qiskit/qiskit-terra/pull/8322#issuecomment-1181595235

Indeed, many property json files contain gates with gate_error==1

$ rgrep '"gate_error", "unit": "", "value": 1}' qiskit -l
qiskit/providers/fake_provider/backends/rochester/props_rochester.json
qiskit/providers/fake_provider/backends/washington/props_washington.json
qiskit/providers/fake_provider/backends/cambridge/props_cambridge_alt.json
qiskit/providers/fake_provider/backends/cambridge/props_cambridge.json
qiskit/providers/fake_provider/backends/manhattan/props_manhattan.json

Moreover, many exploratory backends have errors==1 somewhere, but some calibrations are better than others. So it is important to show the relative amount of gates with error==1.

Additionally, the script tools/update_fake_backends.py might silently fail and it is hard to see why is not doing what it suppose to do. Take the situation of trying to update a backend you dont have access to. It runs without any output, but does not generate the expected files.

In this PR, the script outputs when some of the args.backends did not get updated or if some of the json files were skipped.

This is how it looks:

$ ./tools/update_fake_backends.py --hub <redacted> ibm_washington

ibm_washington
==============
Readout errors == 1:
 * qubit 3
Gate errors == 1:
 * cx 96, 109
 * cx 109, 96
 * cx 118, 119
 * cx 3, 4
 * cx 10, 9
 * cx 9, 10
 * cx 119, 118
 * cx 4, 3
╒═══════════════╤═════════════════════════════════╤═════════════════════════════════════╕
│    error == 1 │  new 2022-07-24 09:02:23+02:00  │  current 2022-04-12 23:42:47+09:00  │
╞═══════════════╪═════════════════════════════════╪═════════════════════════════════════╡
│ readout error │          1/127 (0.79%)          │            0/127 (0.00%)            │
├───────────────┼─────────────────────────────────┼─────────────────────────────────────┤
│      cx error │          8/284 (2.82%)          │            6/284 (2.11%)            │
├───────────────┼─────────────────────────────────┼─────────────────────────────────────┤
│     all gates │          8/919 (0.87%)          │            6/919 (0.65%)            │
╘═══════════════╧═════════════════════════════════╧═════════════════════════════════════╛

In addition, I added a parameter --datetime to be able to fetch specific snapshots, like suggested here.

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[coveralls]

Pull Request Test Coverage Report for Build 3146527252

• 0 of 0 changed or added relevant lines in 0 files are covered.
• 11 unchanged lines in 1 file lost coverage.
• Overall coverage increased (+0.003%) to 84.492%

---

Files with Coverage Reduction	New Missed Lines	%
qiskit/compiler/transpiler.py	11	89.71%
<!--	Total:	11

Totals
Change from base Build 3146373335:	0.003%
Covered Lines:	60199
Relevant Lines:	71248

---

💛 - Coveralls

[1ucian0]

I added some extra explanation and follow the advice in https://github.com/Qiskit/qiskit-terra/pull/8336#discussion_r947289397

ibm_washington
==============
Broken operations (gates with errors == 1)
 * cx 96, 109
 * cx 109, 96
 * cx 118, 119
 * cx 3, 4
 * cx 10, 9
 * cx 9, 10
 * cx 119, 118
 * cx 4, 3
╒═════════════════════════════════════╤═════════════════════════════════╤═════════════════════════════════════╕
│                                     │  new 2022-07-23 23:10:17+02:00  │  current 2022-04-11 14:24:11+02:00  │
╞═════════════════════════════════════╪═════════════════════════════════╪═════════════════════════════════════╡
│                broken cx / total cx │          8/284 (2.82%)          │            6/284 (2.11%)            │
├─────────────────────────────────────┼─────────────────────────────────┼─────────────────────────────────────┤
│ broken operations / total operation │          8/919 (0.87%)          │            6/919 (0.65%)            │
╘═════════════════════════════════════╧═════════════════════════════════╧═════════════════════════════════════╛
The calibration you are pulling (in the "new" column) contain some broken error values (when the error is 1). However, if the rate of broken errors is better than the current one, you might want to update the files.

[1ucian0]

Closing in favor of https://github.com/Qiskit/qiskit-ibm-runtime/pull/1262 as IBM specific fake backends are moving to https://github.com/Qiskit/qiskit-ibm-runtime