Update PushoverHandler.php
Update PushoverHandler.php

.. according to the feedback @stof gave
yegortokmakov/monolog,webwlsong/monolog,dracony/monolog,oswaldderiemaecker/monolog,aeryaguzov/monolog,tavrij/test,netgusto/monolog,mbrevda/monolog,prgTW/monolog,printerpam/monolog,cherrytech/monolog,rap2hpoutre/monolog,yaoshanliang/monolog,dangnguyen27/monolog,0x46616c6b/monolog,JeroenDeDauw/monolog,thiagotalma/monolog,supre/monolog,JCook21/monolog,chinaweilu/monolog,pomaxa/monolog,bd808/monolog,esalter/monolog,Seldaek/monolog,gencer/monolog,localheinz/monolog,dailymotion/monolog,brendo/monolog,KevinMGranger/monolog,entwu/monolog,deguif/monolog,lyrixx/monolog,Sgoettschkes/monolog