[Bug]: Documentation on getting linter and yapf to run unclear

### What happened?

I tried to follow [this documentation](https://cwiki.apache.org/confluence/display/BEAM/Python+Tips#PythonTips-LintandFormattingChecks) to be able to run the linter locally. The following command failed

```
> ../../gradlew lint
```

with

```
> Task :sdks:python:test-suites:tox:py37:setupVirtualenv FAILED
sh: python3.7: command not found

> Task :sdks:python:setupVirtualenv FAILED
sh: python3.8: command not found

FAILURE: Build completed with 2 failures.
```

It would also have been helpful to rewrite in that section that the commands are supposed to be run in `sdks/python`.

### Issue Priority

Priority: 2

### Issue Component

Component: beam-community