package/php-gnupg: bump version to 1.5.0

Other changes:
  - Change --with-gnupg=$(STAGING_DIR)/usr/include to
  --with-gnupg=$(STAGING_DIR)/usr as the make system appends /include to the
    gnupgp path now.

Signed-off-by: Adam Duskett <aduskett@gmail.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>