Implement 'project-path' for the load-cache and save-cache commands

[jjacque]

When having a reusable GH Actions job taking a directory as parameter, it can be useful to be able to set the path to the go.sum file as defining working_directory with parameters.XXX is not allowed.
For example:

jobs:
  go-check:
    executor:
      name: go/default
      tag: "1.21"
    parameters:
      dir:
        type: string
    steps:
      - checkout
      - go/load-cache:
          sumpath: "<< parameters.dir >>/go.sum"
      - run:
          name: Install dependencies
          command: |
            cd << parameters.dir >>
            go mod download
      - run:
          name: GolangCI Lint
          command: |
            cd << parameters.dir >>
            golangci-lint run
      - go/save-cache:
          sumpath: "<< parameters.dir >>/go.sum"