Add release workflow

[asbjornu]

This adds a release workflow that will add to the existing test workflow, which in total should make the CI/CD pipeline look like this:

1. Pull requests are tested with various tools and reported with GitHub Checks so it's easy to see the condition of a PR.
2. All pull requests need to be reviewd by a code owner (see Propose maintinaing a contributors.md file to manage access changes #61).
3. When a PR has all green checks and an approved review, it will be merged to master.
4. All commits to master will invoke the release pipeline to release a pre-release package to the GitHub Package Registry.
5. Once we are happy with the state of master a maintainer creates a new GitHub Release versioned according to SemVer 2.0.
6. The release will also create a tag, which will invoke a new release workflow, this time for a stable release to NuGet.org.

Thoughts, comments and general feedback is welcome.

[codecov]

Codecov Report

Merging #58 into master will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master      #58   +/-   ##
=======================================
  Coverage   68.59%   68.59%           
=======================================
  Files          22       22           
  Lines        4053     4053           
  Branches     1028     1028           
=======================================
  Hits         2780     2780           
  Misses       1130     1130           
  Partials      143      143           

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[goofballLogic]

Can we open an issue for this to discuss the principles we're aiming for. Is it related to #60 ?

[asbjornu]

Can we open an issue for this to discuss the principles we're aiming for. Is it related to #60 ?

Even if we decide to do a rewrite, having a working CI/CD pipeline is going to be a requirement. So getting this up in working order and merged would benefit a greenfield codebase just as much as the current one.

[asbjornu]

@goofballLogic, in #60 (comment) you asked:

Is there anything you can use help with on #58 ?

Indeed it is. I haven't spent much time trying to figure this one out, but currently the build is failing at the NuGet Pack step with the following exception:

##[error]/opt/hostedtoolcache/dncs/2.1.401/x64/sdk/2.1.401/Sdks/NuGet.Build.Tasks.Pack/buildCrossTargeting/NuGet.Build.Tasks.Pack.targets(199,5): error NU5026: The file '/home/runner/work/json-ld.net/json-ld.net/src/json-ld.net/bin/Debug/netcoreapp2.1/json-ld.net.dll' to be packed was not found on disk. [/home/runner/work/json-ld.net/json-ld.net/src/json-ld.net/json-ld.net.csproj]
##[error]Process completed with exit code 1.

If anyone can assist in figuring out why /home/runner/work/json-ld.net/json-ld.net/src/json-ld.net/bin/Debug/netcoreapp2.1/json-ld.net.dll is missing (or how it can be excluded from consideration by dotnet pack if it shouldn't be existing), that would be very helpful.

[goofballLogic]

done #64

[stale]

This issue has been automatically marked as stale because it has not had recent activity. After 30 days from now, it will be closed if no further activity occurs. Thank you for your contributions.

[asbjornu]

This won't be tested properly until it's merged to master and we tag a commit, which I suggest we do soon as it's quite a while since the last release. I'll of course fix problems that arise during the next release.

[goofballLogic]

Happy to merge on that basis.