Update mockery/mockery requirement from 1.0.x-dev to 1.2.2 (#171)

Updates the requirements on [mockery/mockery](https://github.com/mockery/mockery) to permit the latest version.
- [Release notes](https://github.com/mockery/mockery/releases)
- [Changelog](https://github.com/mockery/mockery/blob/master/CHANGELOG.md)
- [Commits](https://github.com/mockery/mockery/commits/1.2.2)
Signed-off-by: Ndependabot[bot] <support@dependabot.com>

composer.json

@@ -8,7 +8,7 @@
     },
     "require-dev": {
         "phpunit/phpunit": "^5.7 || ^7.5",
-        "mockery/mockery": "1.0.x-dev"
+        "mockery/mockery": "1.2.2"
     },
     "autoload": {
         "psr-4": {