gradle: upgrade templates

Signed-off-by: Ferry Huberts <ferry.huberts@pelagic.nl>
gradle: upgrade to 1.12

Signed-off-by: Ferry Huberts <ferry.huberts@pelagic.nl>
gradle: add jacoco

Signed-off-by: Ferry Huberts <ferry.huberts@pelagic.nl>
gradle: use the latest jacoco plugin

Signed-off-by: Ferry Huberts <ferry.huberts@pelagic.nl>