Bug in travis submitting code coverage to Coveralls

I think there is a bug in the TravisCI in submitting the coverage reports to Coveralls. I* have been getting the following error:

The command “julia --color=yes -e “if VERSION < v"0.7.0-DEV.5183"; cd(Pkg.dir("${JL_PKG}")); else using Pkg; end; Pkg.add("Coverage"); using Coverage; Coveralls.submit(process_folder())”” exited with 127.

There have been no substantive changes to this package since a previous submission which passed this so I think there has been a change somewhere which has caused the issue (Julia 1.1 release?). The .travis.yml code I am using is here

Anyone know what is going on here? Potentially there is a bug or the setup I was using to upload to coveralls is no longer supported.

Probably Coverage submission broken: undefined symbol: mbedtls_x509_crt_verify_restartable · Issue #198 · JuliaCI/Coverage.jl · GitHub.