* Bump go versions in .github/workflows/go.yml
These are very out of date and it's causing persistent failures in the
fuzz CI step.
* Remove GOPATH=$GOROOT assignment
go1.16 shows a warning:
"warning: GOPATH set to GOROOT (/opt/hostedtoolcache/go/1.16.0/x64) has no effect"
This also removed the codecov that was still done. We could potentially
re-add as an action, but I don't really miss it. Add testing for 1.14
and 1.15 (it's very fast now).
Fuzzing needs to stay on 1.14 due to brokeness of some kind.
Signed-off-by: Miek Gieben <miek@miek.nl>
This bumps Travis CI to the last two supported golang releases, as
documented in the readme: go1.14 and go1.15.
It also bumps the GitHub Code Action CI to go1.14 as it doesn't yet
supported go1.15 (see actions/setup-go#74).