Convert null values to empty strings (#185)

To avoid deprecation warnings in newer PHP:
```
PHP Deprecated:  str_replace(): Passing null to parameter #3 ($subject)
of type array|string is deprecated in
/Users/isla/source/wp-cli-dev/php-cli-tools/lib/cli/table/Tabular.php on
line 30
```

Fix removal of trailing tab / whitespace in tabular table (#184)

Previously the final table output was trimmed with the intention of
removing the last newline. This had an unintended side effect of
removing the tab characters from empty columns in the specific case
where the last row had one or more empty columns at the end of the row.
This makes sure we are only removing the newline character as intended.

Add a new unit test to verify this behavior as well.

Support line breaks and tab replacement in tabular table values (#182)

This adds the same functionality from both #179 and #181 to the tabular
table output. In WP CLI behat tests, the 'table containing rows' check
can only use tabular output so we need to fix it here in order for tests
to work.

Replace tabs in tables with 4 spaces (#181)

* Replace tabs in tables with 4 spaces

* Move to `padColumn`

* Cast to string

Merge pull request #176 from wp-cli/update-phpunit-config

Merge pull request #172 from wp-cli/fix/unit-tests

Fix unit tests

Merge pull request #170 from kodie/fix-maxFlag-and-maxOption-typo

PHP 8.2: strwidth() & Colors::pad()/decolorize() should always work w…

…ith a string (#163)

Update to WPCS v3 (#161)

Prevent warnings in PHP 8.2 when `$col_values` is empty (#160)