v1.2.1

Please note that this release is a source code breaking change to 1.2.0.
See #419 for more information.

• Upgrade cosmwasm from 1.2.0 to 1.2.2
• Upgrade tempfile
• Create static build for mac libwasmvmstatic_darwin.a (#387)
• Remove tendermint-db dependency by creating a custom iterator interface (#405)
• Print Rust panics to stderr (#396)