Bump up Go version to 1.19

What's Changed

• Add xml nested elements example by @devlights in #572
• Add go list -m -versions example by @devlights in #573
• Add coverage html out example by @devlights in #574
• Add testing with shuffle option example by @devlights in #575
• Add go test count option example by @devlights in #576
• Move testing examples to examples/testing by @devlights in #577
• Add-send-signal-example by @devlights in #578
• Add osop/listprocesses.go by @devlights in #579
• Update-gitpod-docker-image by @devlights in #580
• Bump up Go1.19 by @devlights in #581

Full Changelog: v0.4.4...v0.4.5