v0.8.0-java8

What's Changed

• Adds json support for spray-json by @danlaudk in #336 (ported to java8 by @jbwheatley)
• Update consumer to 4.1.40 in java8 by @jbwheatley in #334
• Update weaver-cats, weaver-core to 0.8.1 in java8 by @jbwheatley in #335
• Update scala-collection-compat to 2.9.0 in java8 by @jbwheatley in #340

Full Changelog: v0.7.0-java8...v0.8.0-java8