[release/8.0] Bump Microsoft.OpenApi.Readers

Bumps [Microsoft.OpenApi.Readers](https://github.com/Microsoft/OpenAPI.NET) from 1.6.14 to 1.6.15.
- [Release notes](https://github.com/Microsoft/OpenAPI.NET/releases)
- [Commits](microsoft/OpenAPI.NET@1.6.14...1.6.15)

---
updated-dependencies:
- dependency-name: Microsoft.OpenApi.Readers
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <[email protected]>

eng/dependabot/independent/Versions.props

@@ -6,7 +6,7 @@
     <AzureStorageBlobsVersion>12.20.0</AzureStorageBlobsVersion>
     <AzureStorageQueuesVersion>12.18.0</AzureStorageQueuesVersion>
     <MicrosoftIdentityWebVersion>2.19.1</MicrosoftIdentityWebVersion>
-    <MicrosoftOpenApiReadersVersion>1.6.14</MicrosoftOpenApiReadersVersion>
+    <MicrosoftOpenApiReadersVersion>1.6.15</MicrosoftOpenApiReadersVersion>
     <SystemPrivateUriVersion>4.3.2</SystemPrivateUriVersion>
     <SystemSecurityPrincipalWindowsVersion>5.0.0</SystemSecurityPrincipalWindowsVersion>