ArduinoBearSSL - adding root certificates

That file is generated from the contents of this directory:

You should build the Bear SLL project (BearSSL - Main) on your PC to get the "brssl" program. Navigate to your extras/TrustAnchors directory and run brssl with the 'chain' argument to generate a new BearSSLTrustAnchors.h file that you can put in your source directory.