lints: new black complains

[jku]

Lint fails on CI currently

lint run-test: commands[0] | black --check --diff tuf/api tuf/ngclient examples tests
--- examples/repo_example/hashed_bin_delegation.py	2022-01-31 12:38:07.681056 +0000
+++ examples/repo_example/hashed_bin_delegation.py	2022-01-31 12:38:35.919966 +0000
@@ -72,11 +72,11 @@
 PREFIX_LEN = len(f"{(NUMBER_OF_BINS - 1):x}")  # ... 2.
 #
 # Compared to decimal, hexadecimal numbers can express higher numbers with
 # fewer digits and thus further decrease metadata sizes. With the above prefix
 # length of 2 we can represent at most ...
-NUMBER_OF_PREFIXES = 16 ** PREFIX_LEN  # ... 256 prefixes, i.e. 00, 01, ..., ff.
+NUMBER_OF_PREFIXES = 16**PREFIX_LEN  # ... 256 prefixes, i.e. 00, 01, ..., ff.
 #
 # If the number of bins is a power of two, hash prefixes are evenly distributed
 # over all bins, which allows to calculate the uniform size of ...
 BIN_SIZE = NUMBER_OF_PREFIXES // NUMBER_OF_BINS  # ... 8, where each bin is
 # responsible for a range of 8 prefixes, i.e. 00-07, 08-0f, ..., f8-ff.
would reformat examples/repo_example/hashed_bin_delegation.py

Oh no! 💥 💔 💥
1 file would be reformatted, 31 files would be left unchanged.
ERROR: InvocationError for command /home/runner/work/python-tuf/python-tuf/.tox/lint/bin/black --check --diff tuf/api tuf/ngclient examples tests (exited with code 1)
___________________________________ summary ____________________________________
ERROR:   lint: commands failed
Error: Process completed with exit code 1.

Fixing this of course fails lint with older black but 🤷

[jku]

as a side note: I think we'll have to start pinning -dev requirements as well -- CI failures should not depend on when the CI run happens

[MVrachev]

From what I understand, fixing this will require following the new black recommendations and pinning the current black version (which at the time of writing this is 22.1.0) inside requirements-dev.txt. @jku am I correct?

If I am correct, then I can submit a pr for this today.

[jku]

Thank you. No need to pin as part of this PR (developers will have to wipe local tox caches, but that's just how tox works). A fix for repo_example is appreciated