Run CI and deploy docs on tags

[DilumAluthge]

Fixes #35

[DilumAluthge]

@chriselrod After you merge this PR, you'll need to:

1. Bump the version number in Project.toml
2. Register a new release using Registrator
3. Wait for the General PR to be auto-merged
4. Wait for TagBot to create the new tag

Once TagBot creates the new tag, this should cause CI to run on the new tag, which will build and deploy the docs for the new tag and set up the "stable" docs alias.

[codecov]

Codecov Report

Merging #36 (fefeee3) into master (7517e60) will not change coverage.
The diff coverage is n/a.

@@            Coverage Diff            @@
##            master       #36   +/-   ##
=========================================
  Coverage   100.00%   100.00%           
=========================================
  Files            4         4           
  Lines          112       122   +10     
=========================================
+ Hits           112       122   +10     

Impacted Files	Coverage Δ
src/atomics.jl	100.00% <0.00%> (ø)
src/threadtasks.jl	100.00% <0.00%> (ø)
src/ThreadingUtilities.jl	100.00% <0.00%> (ø)

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[chriselrod]

Great, docs are now working: https://juliasimd.github.io/ThreadingUtilities.jl/stable