v1.5.0

• Feature / Fix: Support PHP 7.4 by skipping unneeded cleanup of exception trace args.
  (#33 by @clue)

• Clean up test suite and add .gitattributes to exclude dev files from exports.
  Run tests on PHP 7.4, PHPUnit 9 and simplify test matrix.
  Link to using SSH proxy (SSH tunnel) as an alternative.
  (#27 by @clue and #31, #32 and #34 by @SimonFrings)