Hashmap Driver v0.6.0

What's Changed

• Merging Caches into one version by @madflojo in #2
• Restructuring Benchmarks by @madflojo in #3
• Updating README by @madflojo in #4
• Adding Banner to README by @madflojo in #5

Full Changelog: drivers/hashmap/v0.5.0...drivers/hashmap/v0.6.0