Arbitrum Token Bridge v1.2.2

What's Changed

• Add sig check to CI by @gvladika in #78
• Slither integration by @gvladika in #79
• Fix gaps found by mutation testing by @gvladika in #69
• Check that Weth gateways are registered in the deployment test by @gvladika in #72
• Add unit tests for token bridge L2 contracts by @gvladika in #74
• Orbit verify by @gvladika in #85
• Add e2e tests to CI by @gvladika in #51
• Handle non-18-decimal fee tokens in token bridge creator by @gvladika in #86

Full Changelog: v1.2.1...v1.2.2