Upgrade out of date Black to a version supporting Python 3.9 to avoid it erroring out

[CAM-Gerlach]

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Currently, our code supports Python 3.7-3.9, the last of which has been out for almost a year now. Accordingly, I specify target versions from 3.7 through 3.9 in my Black config, i.e. target-version = ["py37", "py38", "py39"]. However, given the Black release, 20.8, is over a year old and is the last to not support Python 3.9 released a couple months later, Black errors out on every file due to not recognizing the target-version key, and thus rendering it unusable for me through Mega-Linter.

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Upgrade Black to a version >=21.4 that supports Python 3.9; preferably the latest version that fixes issues with the soon to be default experimental-string-processing that many projects are using in production now, as well as other issues.

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Don't upgrade Black; which will block support for language versions newer than Python 3.8, as well as not take advantage of the latest features and bug fixes.

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Thanks!

[nvuillam]

Released in latest/insiders, please can you confirm that it's ok now ?

Note: this CI job must be completed before testing is available with latest/insiders tag

[CAM-Gerlach]

Hey @nvuillam , thanks for your quick work on this! Unfortunately it doesn't seem to have worked, though its quite possible I did something wrong. I set the action to uses: nvuillam/mega-linter@insiders as the Readme instructs, and I could see in the build output that the latest builds were getting pulled and I verified #680 is now fixed. However, the version of Black is still shown as - Using [black v20.8] https://black.readthedocs.io/en/stable/ and I consequently get the same error on every file.

You can check out what I have so far on r-spacex/submanager#11 ... Let me know if there's something else I should try. Thanks!

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[CAM-Gerlach]

Hey @nvuillam thanks for working on this. Any updates, or anything else you need from me? Thanks!

[nvuillam]

@CAM-Gerlach now black version is 21.9 in Mega-Linter, is it ok ?