update image title and alt text

2018-05-12 16:10:54 +00:00 · 2018-05-12 16:10:54 +00:00 · 32e57aa9cb
--- a/README.md
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-!["Greenlock Logo"](https://git.coolaj86.com/coolaj86/greenlock.js/raw/branch/master/logo/greenlock-1063x250.png)
+![Greenlock Logo](https://git.coolaj86.com/coolaj86/greenlock.js/raw/branch/master/logo/greenlock-1063x250.png "Greenlock Logo")
 Greenlock&trade; for Express.js
 =================