7.4.9

Dependencies:

• 9a1c9ca build(deps): bump actions/checkout from 2.3.5 to 2.4.0 (#530) @dependabot[bot]
• a8ac17b build(deps): bump Microsoft.SourceLink.GitHub in /src (#532) @dependabot[bot]
• 590c67c build(deps): bump Roslynator.Analyzers from 3.2.2 to 3.3.0 in /src (#536) @dependabot[bot]
• 5ac9fb9 build(deps): bump actions/setup-dotnet from 1.8.2 to 1.9.0 (#535) @dependabot[bot]

Fixes:

• aa32432 Fix threading issue in observable cache. Fixes #538 (#539) @RolandPheasant

Housekeeping:

• ee1688e housekeeping: automatically lock old issues and PRs @glennawatson