feat: Add addional GH token descriptor name

[ZPascal]

Support token as primary input name

Adds token as the preferred input name, aligning with the naming convention used by actions/checkout. The existing github_token input continues to work as a fallback for backwards compatibility.

Usage

- uses: ad-m/github-push-action@master
  with:
    token: ${{ secrets.GITHUB_TOKEN }}

Changes

• token is resolved first, falling back to github_token if not set
• Updated error message to reference token
• No breaking changes — existing workflows using github_token are unaffected

Issue

fix: #56

Test

• Github action run

[Copilot]

Pull request overview

Adds support for a token input name (matching common GitHub Actions conventions) while keeping github_token for backwards compatibility, and updates the wrapper logic/docs accordingly.

Changes:

• Introduces a new token input in action.yml.
• Resolves auth token in start.js via INPUT_TOKEN || INPUT_GITHUB_TOKEN and forwards it to start.sh.
• Updates README usage examples and inputs table; updates the missing-token error message.

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 3 comments.

File	Description
action.yml	Adds new token input (but current defaults create a precedence regression).
start.js	Resolves token from token/github_token and forwards the resolved token to the shell script.
start.sh	Updates the missing-token error message to reference token.
README.md	Documents token usage and adds token to the inputs table.

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[Copilot]

Pull request overview

Copilot reviewed 4 out of 4 changed files in this pull request and generated 3 comments.

[ZPascal]

@ad-m or @jackton1, could you please take a look at the change? What do you think of it?