Update Readme - remove incorrect youtube link for CBMC. (#67)

Author: abhidixi11

README.md

@@ -2,7 +2,7 @@
 
 This repository contains the coreMQTT library that has been optimized for a low memory footprint.  The coreMQTT library is fully compliant with the [MQTT 3.1.1](http://docs.oasis-open.org/mqtt/mqtt/v3.1.1/mqtt-v3.1.1.html) standard.  It has no dependencies on any additional libraries other than the standard C library, a customer-implemented network transport interface, and *optionally* a user-implemented platform time function.  This library is distributed under the [MIT Open Source License](LICENSE).
 
-This library has gone through code quality checks including verification that no function has a [GNU Complexity](https://www.gnu.org/software/complexity/manual/complexity.html) score over 8, and checks against deviations from mandatory rules in the [MISRA coding standard](https://www.misra.org.uk/MISRAHome/MISRAC2012/tabid/196/Default.aspx).  Deviations from the MISRA C:2012 guidelines are documented under [MISRA Deviations](MISRA.md). This library has also undergone both static code analysis from [Coverity static analysis](https://scan.coverity.com/) and validation of memory safety and functional correctness proof through the  [CBMC automated reasoning tool](https://www.youtube.com/watch?v=YwQHAPRhQkI&feature=youtu.be&t=1721).  
+This library has gone through code quality checks including verification that no function has a [GNU Complexity](https://www.gnu.org/software/complexity/manual/complexity.html) score over 8, and checks against deviations from mandatory rules in the [MISRA coding standard](https://www.misra.org.uk/MISRAHome/MISRAC2012/tabid/196/Default.aspx).  Deviations from the MISRA C:2012 guidelines are documented under [MISRA Deviations](MISRA.md). This library has also undergone both static code analysis from [Coverity static analysis](https://scan.coverity.com/) and validation of memory safety and functional correctness proof through the CBMC automated reasoning tool.
 
 ## MQTT Config File