Update solc

[dstallenberg]

Describe the bug
The framework complains about invalid opcodes in the DateTime contract. This is probably due to the usage of an old solidity compiler.

To Reproduce
Steps to reproduce the behavior:

1. Run the tool on the Datetime contract

Expected behavior
It should simply be able to run on any contract regardless of version

[dstallenberg]

Updated relevant dependencies, changed the solc version used by truffle. Still errors.

[dstallenberg]

The following shows a conversation regarding this issue due to the solidity-coverage project.
https://forum.openzeppelin.com/t/unable-to-run-tests-using-ganache-cli-and-open-zepplin-2-4-0/1722

[mitchellolsthoorn]

@dstallenberg is this issue still relevant?

[stale]

This issue has been automatically marked as stale because it has not had recent activity. The resources of our team are limited. This issue will be closed if no further activity occurs.