Vyper

This is a quick patch release to fix a runtime error introduced in `v0.2.6` ([2188](https://github.com/vyperlang/vyper/pull/2188)) that could allow for memory corruption under certain conditions.

Non-breaking changes and improvements:

- Show contract names in raised exceptions (2103)
- Adjust function offsets to not include decorators (2102)
- Raise certain exception types immediately during module-scoped type checking (2101)

Fixes:

- Pop ``for`` loop values from stack prior to returning (2110)
- Type checking non-literal array index values (2108)
- Meaningful output during ``for`` loop type checking (2096)

Fixed
- Do not fold exponentiation to a negative power ([2089](https://github.com/vyperlang/vyper/pull/2089))
- Add `repr` for mappings ([2090](https://github.com/vyperlang/vyper/pull/2090))
- Literals are only validated once ([2093](https://github.com/vyperlang/vyper/pull/2093))