Update tools-init.sh for WordPress 5.9 compatibility

[GaryJones]

A new release of PHPCompatibilityWP has been made: https://github.com/PHPCompatibility/PHPCompatibilityWP/releases/tag/2.1.3

This adds compatibility with WordPress 5.9, so it would be good to get this in place and released to customers before WP 5.9 is made available on the VIP platform later this month.

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Noting that other tools are also behind:

• PHPCS: 3.5.5 -> 3.6.2
• PHPCS Varaible Analysis: 2.11.1 -> 2.11.2
• PHPCompabtility Paragonia: 1.3.0 -> 1.3.1

[gudmdharalds]

Resolved in #228.