[repo] remove ci-concurrency from sln items (open-telemetry#6071)

Co-authored-by: Mikel Blanchard <[email protected]>

Author: SimonCropp

OpenTelemetry.sln

@@ -12,7 +12,6 @@ Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "Solution Items", "Solution
 		.dockerignore = .dockerignore
 		.editorconfig = .editorconfig
 		.gitignore = .gitignore
-		.github\workflows\ci-concurrency.yml = .github\workflows\ci-concurrency.yml
 		CONTRIBUTING.md = CONTRIBUTING.md
 		global.json = global.json
 		LICENSE.TXT = LICENSE.TXT