v0.5.2

This release brings:

1. Support for Solidity 0.8.4, 0.8.5 and 0.8.6

2. Extends the universal quantification support to work over maps. (i.e. forall (address a in m) ... where m is a map works now)

3. Adds the new builtin unchecked_sum() function, which returns the sum of all values in a numeric map/array. As the name suggests, the sum may overflow, and should be used with carefully.

4. The debug events emitted with --debug-events have been changed to a new simpler format, and now support arrays as well as include more identifiers. (forall iterator vars, path identifiers appearing in if_assigned, etc.).

5. Fixed a bug in debug events where identifiers appearing inside of old(...) expressions had their new value reported erroneously.

6. Cleanup of InstrumentationContext and smaller fixes.