Add check for AthGeneration in logParser
Description
Recently a jO with AthGenerationExternals was used and this was not caught in logParser or any other test. (see !265 (merged))
This MR adds a check that throws an error if the release used is not AthGeneration.
Tests
Test 1: Release is AthGeneration externals -> logParser throws an error as expected

Test 2: Behaviour of blacklist test is unaffected (tested with a blacklisted release and error thrown as expected)

Closes #82 (closed)