chore(deps): Bump phpseclib/phpseclib from 3.0.56 to 4.0.1

Bumps [phpseclib/phpseclib](https://github.com/phpseclib/phpseclib) from 3.0.56 to 4.0.1.
- [Release notes](https://github.com/phpseclib/phpseclib/releases)
- [Changelog](https://github.com/phpseclib/phpseclib/blob/master/CHANGELOG.md)
- [Commits](phpseclib/phpseclib@3.0.56...4.0.1)

---
updated-dependencies:
- dependency-name: phpseclib/phpseclib
  dependency-version: 4.0.0
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

composer.json

@@ -18,7 +18,7 @@
 		"ext-simplexml": "*",
 		"mikehaertl/php-pdftk": "^0.14.4",
 		"league/commonmark": "^2.10",
-		"phpseclib/phpseclib": "^3.0"
+		"phpseclib/phpseclib": "^4.0"
 	},
 	"require-dev": {
 		"roave/security-advisories": "dev-master",