chore(master): release 2.3.0

[slo-generator-bot]

🤖 I have created a release beep boop

2.3.0 (2022-10-24)

Features

• add Cloud Monitoring MQL backend (#245) (159f4d5)
• add Prometheus Self exporter for API mode (#209) (53c0fdf)
• add pytype linting (#249) (b622d09)

Bug Fixes

• add timeFrame to retrieve_slo dynatrace (#212) (2db0140)
• make unit tests pass again with elasticsearch 8.x client (#223) (39dd26c)
• prevent gcloud crash with python 3.10 during release workflow (39a257e)
• remove useless and unknown Pylint options (#247) (5053251)
• support custom exporters (#235) (b72b8f4)
• update "Development Status" classifier (c82eea3)

Documentation

• add missing 'method' field in readme (#213) (5d2a9a0)
• add Python 3.9 classifier (#226) (83c36b9)
• document how to write and configure filters in Cloud Monitoring provider (#266) (29ab2e1)

---

This PR was generated with Release Please. See documentation.

[slo-generator-bot]

🤖 Release is at https://github.com/google/slo-generator/releases/tag/v2.3.0 🌻