Upgrade breakpad

It's been a long time (4+ years) since we took a newer version of breakpad. More importantly, however, our version won't build on Ubuntu 20.04 due to changes in glibc since 2.30. We could attempt to backport this fix, but it feels like maybe upgrading is the better choice.

There are two patches we have made to breakpad which need to be ported to this new version:

https://github.com/couchbasedeps/breakpad/commit/4c091b64099114da457a8b1d59fe188009ce8876

https://github.com/couchbasedeps/breakpad/commit/d81e7432748cfd1207814bf20de00e56e3e0a238

I have forked github.com/google/breakpad to github.com/couchbasedeps/google-breakpad, and created a couchbase-20200430 branch from the current master tip. If those changes can be ported back, I can then work on getting it built on all platforms.