This commit changes the way the action determines if running in action
or runner mode. There is now an environment variable that is set at the
beginning of the process and elsewhere in the process, we can check to
see if the variable is set.
* Allow the codeql-action to be run locally
This change allows the codeql-action to be run locally through
[act](https://github.com/nektos/act).
In order to run the action locally, you need to do two things:
1. Add the `CODEQL_LOCAL_RUN: true` environment variable. The only way
I could figure out how to do this was to add it directly in the
workflow file in an `env` block. It _should_ be possible to add it
through a `.env` file and pass it to `act`, but I couldn't get it
working.
2. Run this command `act -j codeql -s GITHUB_TOKEN=<MY_PAT>`
Setting the `CODEQL_LOCAL_RUN` env var will fill in missing env vars
that the action needs, but isn't set by `act`. It will also avoid
making api calls to github that would fail locally.
This is a refactoring discussed in
https://github.com/github/dsp-codeql/issues/36
