Adds new RC012 that checks how environment variables passed as parameters are being used

[david-montano-circleci]

Summary

This PR is meant to prevent errors like this from happening again.
Tackles issue #246 .

Steps

1. identify which parameters are defined as Environment Variables
2. search where those parameters are being used directly inside key entries in the yml files
3. show the user information about incorrect usage of those parameters

Tests

Using a yml like the following:

description: "Save Go modules to cache."
parameters:
  key:
    description: "User-configurable component for cache key. Useful for avoiding collisions in complex workflows."
    type: string
    default: ""
  path:
    description: "Path to cache."
    type: string
    # /home/circleci/go is the GOPATH in the cimg/go Docker image
    default: "/home/circleci/go/pkg/mod"
  project-path:
    description: |
      The path to the directory containing your Go project files: go.mod, go.sum.
      Defaults to $CIRCLE_WORKING_DIRECTORY.
    type: string
    default: $CIRCLE_WORKING_DIRECTORY
steps:
  - save_cache:
      key: v1-<< parameters.key >>-go-mod-{{ arch }}-{{ checksum "go.sum" }}
      key: v1-<< parameters.key >>-go-mod-{{ arch }}-{{ checksum "<< parameters.project-path >>/go.sum" }}
      paths:
        - << parameters.path >>
  - run:
      name: thing
      command: echo "<< parameters.project-path >>"
  - run: echo "<< parameters.project-path >>"

The review step outputs this:

$ bats -f "RC012"  --show-output-of-passing-tests src/scripts/review.bats

review.bats
 ✗ RC012: Incorrect usage of environment variables set as default parameter detected.
   (in test file src/scripts/review.bats, line 324)
     `exit 1' failed
   
   File: "./src/jobs/david.yml"
   Parameter definition line: 17
   Parameter name: project-path
   Parameter value: $CIRCLE_WORKING_DIRECTORY
   
   The parameter "project-path" was initialized as an Environment Variable: "$CIRCLE_WORKING_DIRECTORY"
   It is being used by an orb key parameter ("steps.0.save_cache.key") in line 21 which is not permitted.
   ---
   v1-<< parameters.key >>-go-mod-{{ arch }}-{{ checksum "<< parameters.project-path >>/go.sum" }}
   ---
   
   "default" parameters referencing environment variables cannot be used directly in key properties.

1 test, 1 failure

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