v7.0.0

Breaking changes:

• Update project and deps to PureScript v0.15.0 (#59 by @JordanMartinez)
• Drop deprecated MonadZero instance (#59 by @JordanMartinez)
• Drop Proxy2/Proxy3 usage in favor of just Proxy (#59 by @JordanMartinez)

New features:

• Provide Arbitrary-less law checks (#36 by @matthewleon, #57 by @JordanMartinez)

Other improvements:

• Fix integer overflow error in test for Ints (#58 by @JordanMartinez)