Add JetBrains PhpStorm Attributes package to monorepo dev-dependencies

[caendesilva]

Adds https://github.com/JetBrains/phpstorm-attributes to the development dependencies for this monorepo. This will prevent us from getting undefined class errors from static analysis when using those attributes. This will not affect any of the downstream split packages.

[codecov]

Codecov Report

Merging #905 (94278b9) into master (afab768) will not change coverage.
The diff coverage is n/a.

@@              Coverage Diff              @@
##              master      #905     +/-   ##
=============================================
  Coverage     100.00%   100.00%             
- Complexity      1281      2562   +1281     
=============================================
  Files            147       294    +147     
  Lines           3354      6708   +3354     
=============================================
+ Hits            3354      6708   +3354     

Impacted Files	Coverage Δ
...res/DataCollections/Facades/MarkdownCollection.php	100.00% <0.00%> (ø)
...ork/src/Foundation/Concerns/ForwardsFilesystem.php	100.00% <0.00%> (ø)
...ork/src/Framework/Features/Templates/Homepages.php	100.00% <0.00%> (ø)
...ures/BuildTasks/PostBuildTasks/GenerateSitemap.php	100.00% <0.00%> (ø)
...kages/framework/src/Markdown/MarkdownConverter.php	100.00% <0.00%> (ø)
...es/framework/src/Console/Commands/DebugCommand.php	100.00% <0.00%> (ø)
...evelop/packages/framework/src/Facades/Features.php	100.00% <0.00%> (ø)
...framework/src/Console/Commands/MakePageCommand.php	100.00% <0.00%> (ø)
...uildTasks/PostBuildTasks/GenerateBuildManifest.php	100.00% <0.00%> (ø)
...packages/framework/src/Pages/Concerns/HydePage.php	100.00% <0.00%> (ø)
... and 137 more

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