Prepare release 1.50.0

[albertteoh]

Updates changelog, release.md and jaeger-ui submodule for v1.50.0

Checklist

• I have read https://github.com/jaegertracing/jaeger/blob/master/CONTRIBUTING_GUIDELINES.md
• I have signed all commits

[albertteoh]

• Update URL and jaeger-ui submodule once Prepare release v1.34.0 jaeger-ui#1849 is merged.

[albertteoh]

Done in: f6b60e1 and f0a89e2

[codecov]

Codecov Report

Attention: 38 lines in your changes are missing coverage. Please review.

Files	Coverage Δ
cmd/agent/app/configmanager/grpc/manager.go	100.00% <100.00%> (ø)
cmd/agent/app/configmanager/metrics.go	100.00% <100.00%> (ø)
cmd/agent/app/processors/thrift_processor.go	100.00% <100.00%> (ø)
cmd/agent/app/reporter/flags.go	100.00% <ø> (ø)
cmd/agent/app/reporter/grpc/builder.go	95.38% <100.00%> (+0.07%)	⬆️
cmd/agent/app/reporter/grpc/collector_proxy.go	100.00% <100.00%> (ø)
cmd/agent/app/reporter/grpc/reporter.go	100.00% <100.00%> (ø)
cmd/agent/app/reporter/reporter.go	100.00% <100.00%> (ø)
cmd/agent/app/testutils/in_memory_reporter.go	100.00% <100.00%> (ø)
cmd/collector/app/collector.go	87.90% <100.00%> (ø)
... and 65 more

... and 27 files with indirect coverage changes

📢 Thoughts on this report? Let us know!.

[yurishkuro]

Strange that build started failing in this PR only, but here's a fix: #4807.

[albertteoh]

Checks passed with a false positive codecov check, @yurishkuro.

[yurishkuro]

My guess codecov is having a bad day