[ci] Move CI to GitHub Actions (fixes #286)

[jameslamb]

This PR moves {pkgnet}'s CI from Travis to GitHub Actions, in response to the all the recent changes in Travis (see #286).

Today on main, we only test with the latest version of R. I originally tried to add jobs for both R 4.0 and R 3.6 in this PR, but 3.6 was giving me some problems so I decided to cut that out of the scope for this PR.

This PR also fixes this issue in the unit tests.

Attaching package: 'testthat'

The following object is masked from 'package:pkgnet':

    SummaryReporter

That fix should really be its own PR but I already did it here because while debugging, I think it might be related to soome issues I was facing.

[codecov-io]

Codecov Report

Merging #287 (e1915ac) into main (1d5a01c) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##             main     #287   +/-   ##
=======================================
  Coverage   92.60%   92.60%           
=======================================
  Files          12       12           
  Lines         946      946           
=======================================
  Hits          876      876           
  Misses         70       70           

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 1d5a01c...e1915ac. Read the comment docs.

[jameslamb]

Attaching package: 'testthat'

The following object is masked from 'package:pkgnet':

    SummaryReporter

😱 😱 😱

[jameslamb]

ok I think this is ready for review!

[jayqi]

One last comment but overall looks good to me. Thanks for going through this!

[jayqi]

Did you check if we need these dependencies? I would've expected that between r-lib/actions/setup-r, r-lib/actions/setup-pandoc, and r-lib/actions/setup-tinytex we'd be covered. If it's the case that we don't need this bash script, you could move the remotes stuff into ci.yml under run.

[jameslamb]

I looked around tonight and found that r-lib/actions/setup-r now seems to install qpdf and checkbashisms for you (it used to not), so I'll try removing those.

But some of these are needed by other packages in {pkgnet}'s dependencies. Only necessary on Linux because CRAN doesn't prepare precompiled binaries on Linux, so all those things need to be built from source.

libcurl4-openssl-dev \
libfribidi-dev \
libharfbuzz-dev \
curl \

[bburns632]

Seconded. Thanks for this effort to fix the CI!!