Update actions to v3 to use node.js v16 and master branch

[jishnub]

Let's also see if the documentation builds correctly in this PR

[coveralls]

Pull Request Test Coverage Report for Build 3307675532

Warning: This coverage report may be inaccurate.

This pull request's base commit is no longer the HEAD commit of its target branch. This means it includes changes from outside the original pull request, including, potentially, unrelated coverage changes.

• For more information on this, see Tracking coverage changes with pull request builds.
• To avoid this issue with future PRs, see these Recommended CI Configurations.
• For a quick fix, rebase this PR at GitHub. Your next report should be accurate.

Details

• 0 of 0 changed or added relevant lines in 0 files are covered.
• 1 unchanged line in 1 file lost coverage.
• Overall coverage decreased (-0.5%) to 79.907%

---

Files with Coverage Reduction	New Missed Lines	%
src/strang.jl	1	69.23%

Totals
Change from base Build 3264654829:	-0.5%
Covered Lines:	171
Relevant Lines:	214

---

💛 - Coveralls

[codecov]

Codecov Report

Base: 80.37% // Head: 79.90% // Decreases project coverage by -0.46% ⚠️

Coverage data is based on head (169469e) compared to base (a4e72da).
Patch has no changes to coverable lines.

Additional details and impacted files

@@            Coverage Diff             @@
##           master      #58      +/-   ##
==========================================
- Coverage   80.37%   79.90%   -0.47%     
==========================================
  Files           8        8              
  Lines         214      214              
==========================================
- Hits          172      171       -1     
- Misses         42       43       +1     

Impacted Files	Coverage Δ
src/strang.jl	69.23% <0.00%> (-7.70%)	⬇️
src/riemann.jl	100.00% <0.00%> (ø)

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[jishnub]

OK, can replicate the git fetch failure

[JeffFessler]

With the fix in #61 I am pretty optimistic this will work now.
I am going to go ahead and merge this and see. It is easy to refine later if needed (e.g., using latest).

[JeffFessler]

It worked! At last we have docs-dev badge active.
@jishnub please delete the branch if you are satisfied with what was merged,
and please comment on the latest if/when you can. Thanks!

[jishnub]

Tbh I don't know enough about GitHub actions as well. Let's use latest for now if it is working. It's unlikely that we use features that live on the bleeding edge, so latest should be equivalent to stable releases.

[JeffFessler]

OK, I'm testing it in a separate PR #62. Thanks!

[JeffFessler]

For the record, one can use cache@main if you want live on the bleeding edge:
https://github.com/orgs/community/discussions/37052
Maybe sticking with the tagged version @v3 is safer...