Consolidate .coveragerc and .flake8 config int pyproject.toml (locals…

…tack#4477)

* migrate .flake8 config to pyproject.toml through pyflake8
* migrate .coveragerc to pyproject.toml through coverage[toml] extra

minor updates in README; release version 0.12.16

fix patching of "apiStages" in API GW usage plans; release version 0.…

…12.15

release version 0.12.14; reduce verbosity of Kinesis logging

release version 0.12.13

release version 0.12.12

release version 0.12.11

release v0.12.10

release version 0.12.9

release v0.12.8; fix log output for "localstack config" CLI commands