Bump version string to 2.0.2

[abreufilho]

Fixes #162.

The v2.0.2 release was tagged without running step 2 of RELEASE.md (Update the version in config/app.php), so both the v2.0.2 tag and master still carry 'version' => '2.0.1'.

Effect on the released binary:

$ composer global show laravel/forge-cli | grep versions
versions : * v2.0.2

$ forge --version
Forge CLI 2.0.1

Because the self-update check compares this internal string against Packagist, every authenticated command prints a permanent update warning:

==> You Are Using An Outdated Version [v2.0.1] Of Forge CLI. Please Update To [v2.0.2].

This PR restores the invariant master version == last released tag. Note:

• The committed builds/forge PHAR still bakes in the old string; it is regenerated via ./forge app:build during the release (step 3 of RELEASE.md), so I left it untouched rather than commit a non-reproducible binary.
• The already-tagged v2.0.2 binary can't be fixed retroactively; this ensures the next build/tag reports correctly. If you'd rather treat the next build as a fresh release, bump to 2.0.3 instead.