package/php: bump version to 7.4.2

package/php: bump version to 7.4.2

patch 0005 has been sourced from upstream, and can be dropped when
7.4.3 is released.

The mbstrings module used to use a bundled oniguruma library, but now
uses an external one, hence the new dependency on this package for the
mbstrings module.

The hash of the license file has changed due to this change in the
copyright year:

-Copyright (c) 1999 - 2018 The PHP Group. All rights reserved.
+Copyright (c) 1999 - 2019 The PHP Group. All rights reserved.

Signed-off-by: Pascal de Bruijn <p.debruijn@unilogic.nl>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>