doc(README): delete broken link

Author: Damian Rouson

README.md

@@ -11,7 +11,6 @@
 Framework for Extensible Asynchronous Task Scheduling (FEATS)
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-[![Release Downloads][download img]][Releases]
 [![GitHub license][license img]](./LICENSE)
 [![GitHub release][release img]](https://github.com/sourceryinstitute/FEATS/releases/latest)
 [![Download as PDF][pdf img]](https://md2pdf.herokuapp.com/sourceryinstitute/FEATS/blob/master/README.pdf)