Bump backoff from 1.11.1 to 2.0.1 (#279)

Bumps [backoff](https://github.com/litl/backoff) from 1.11.1 to 2.0.1.
- [Release notes](https://github.com/litl/backoff/releases)
- [Changelog](https://github.com/litl/backoff/blob/master/CHANGELOG.md)
- [Commits](litl/backoff@v1.11.1...v2.0.1)

---
updated-dependencies:
- dependency-name: backoff
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

requirements.txt

@@ -4,9 +4,9 @@
 #
 #    pip-compile --generate-hashes
 #
-backoff==1.11.1 \
-    --hash=sha256:61928f8fa48d52e4faa81875eecf308eccfb1016b018bb6bd21e05b5d90a96c5 \
-    --hash=sha256:ccb962a2378418c667b3c979b504fdeb7d9e0d29c0579e3b13b86467177728cb
+backoff==2.0.1 \
+    --hash=sha256:8700797e5f45e41ee3bf357137f074a174797016dc9ad3c2b974a955bab92b50 \
+    --hash=sha256:bd6f32d4aff2607a578e847bf5bdb978a0eb1911fe5c0b0a73325328881bb31c
     # via -r requirements.in
 certifi==2021.10.8 \
     --hash=sha256:78884e7c1d4b00ce3cea67b44566851c4343c120abd683433ce934a68ea58872 \