Switch from Travis-Ci to GitHub actions for continuous integration workflow

[froschdesign]

To prepare a pull request following these steps:

• Remove the CHANGELOG.md file (we will be doing changelogs in the milestone descriptions, and those get propagated to tags and release notes)
• Add the workflow file:

  mkdir -p .github/workflows ; cd  .github/workflows ; wget https://gist.githubusercontent.com/weierophinney/9decd19f76b7d9745c6559074053fa65/raw/6ffb33e59796cfec569405139aa65da9396ea5cd/continuous-integration.yml

• Check to see if there are any differences between what the Travis config and the GHA workflow do - don't worry about code coverage - but check for things like: extensions required, any pre-script tasks, etc. (Most of the time, there aren't any). If you see any, either: (1) add a .laminas-ci.json file with required configuration (e.g., adding extensions, adding php.ini settings; see https://github.com/laminas/laminas-ci-matrix-action#configuration for details), or (2) add information to the GHA workflow file (e.g., adding a service such as MySQL, Redis, etc.; see the laminas-db or laminas-cache adapter packages for examples).
• Remove the .travis.yml file.
• Remove the entry for composer.lock from the .gitignore file.
• In the .gitattributes file:
  • Remove the entry for .travis.yml
  • Add an entry for .laminas-ci.json if you created one
  • Add an entry for .github if one does not exist
• Using PHP 7.4, run composer update
• Update the README.md file:
  • Remove any existing badges for Travis and/or Coveralls.
  • Add a badge with the following (substituting in the correct organization and repository name):

    [![Build Status](https://github.com/laminas/laminas-hydrator/actions/workflows/continuous-integration.yml/badge.svg)](https://github.com/laminas/laminas-hydrator/actions/workflows/continuous-integration.yml)

• Add and commit the GHA workflow, the .gitignore and .gitattribute files, the composer.lock file, and the README.md file.
• Push to your fork and create the PR. If there are any QA job failures, fix and push the changes.
• If the package supports PHP ^5.6 | ^7.0, you will need to exclude locked runs for PHP 5.6 - 7.2. The way to do that is to create the .laminas-ci.json file if you haven't already, and ensure it has the following contents:

  {
      "exclude": [
          {"name": "PHPUnit on PHP 5.6 with locked dependencies"},
          {"name": "PHPUnit on PHP 7.0 with locked dependencies"},
          {"name": "PHPUnit on PHP 7.1 with locked dependencies"},
          {"name": "PHPUnit on PHP 7.2 with locked dependencies"}
      ]
  }

[sasezaki]

Remove any existing badges for Travis and/or Coveralls.

I noticed that coverall still exists, and target branch is master.