[release] Core stable release 1.15.3 updates#7125

martincostello merged 3 commits intomainopen-telemetry/opentelemetry-dotnet:mainfrom

otelbot/post-stable-core-1.15.3-updateopen-telemetry/opentelemetry-dotnet:otelbot/post-stable-core-1.15.3-updateCopy head branch name to clipboard