Upgrade to scraperlib v3.4.0 to use VP9

[benoit74]

Partial implementation of #235

• partial because this PR is an update on the v2 branch since v3 is not yet ready
• this also needs to be backported to main branch as well
• tests done
  • run again the scraper => all videos are reencoded with VP9 and reuploaded to cache
  • run again the scraper a second time => all videos are downloaded from cache and are encoded with VP9
• also implement bootstrap v1.0.2 (fixes to code coverage upload)

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

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Additional details and impacted files

```diff @@ Coverage Diff @@ ## v2 #236 +/- ## ==================================== Coverage ? 1.78% ==================================== Files ? 10 Lines ? 954 Branches ? 158 ==================================== Hits ? 17 Misses ? 937 Partials ? 0 ```

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