CI: updated 'build' workflow configuration

CI: updated workflow actions

Merge pull request #83 from casm-lang/feature/100_utf8

UTF8 based test case specification files

Merge pull request #75 from casm-lang/feature/34_comment

Feature/34 comment

RunnerTest: updated diff behavior to ignore CR for now

Merge pull request #71 from casm-lang/bug/choose_expression_is_not_pure

Test if choose expression is correctly marked as in-pure

Building

* fixed test/benchmark integration and building
* fixed a initialization bug in the benchmark runner