Update pear/log requirement to 1.12.*|1.13.*

Updates the requirements on [pear/log](https://github.com/pear/Log) to permit the latest version.
- [Release notes](https://github.com/pear/Log/releases)
- [Commits](https://github.com/pear/Log/commits/1.13.1)

composer.json

@@ -22,7 +22,7 @@
     "require": {
         "php": ">=5.4.0",
         "pear/http_request2": "2.3.*",
-        "pear/log": "1.12.*"
+        "pear/log": "1.12.*|1.13.*"
     },
     "require-dev": {
         "phpunit/phpunit": "*",