Bump up Go version to 1.20

What's Changed

• go fmt ./... by @devlights in #582
• Update Gitpod config file by @devlights in #583
• Update gomy version to v0.5.0 by @devlights in #584
• Add flag.FlagSet example by @devlights in #585
• Add fmt.Append/Appendf/Appendln examples (Go 1.19) by @devlights in #586
• Add url.JoinPath example (Go 1.19) by @devlights in #587
• Add Build constraints "unix" example (Go 1.19) by @devlights in #588
• Add atomic.Int32 example (Go 1.19) by @devlights in #589
• Add simple http long polling example by @devlights in #590
• Add errors.Is() and errors.As() example by @devlights in #591
• Add example/http/httpserver by @devlights in #592
• Add multi dementional array (slice) example by @devlights in #593
• Add crypto/aes ECB, CBC examples by @devlights in #594
• Add crypto/rand.Reader example. by @devlights in #595
• Add rand.Read example by @devlights in #596
• Add declare_empty_slice.go by @devlights in #597
• Add list available GOOS and GOARCH list by @devlights in #598
• Add bcrypt (golang.org/x/crypto/bcrypt) example by @devlights in #599
• Update gomy version to v0.5.3 by @devlights in #600
• Add go tool trace example by @devlights in #601
• Update gomy version to v0.5.6 by @devlights in #602
• Add examples/basic/profiles dir by @devlights in #603
• Add scanop/read_one_input.go by @devlights in #604
• Add scanop/read_multiple_input.go by @devlights in #605
• Add scanop/read_formatted_input.go by @devlights in #606
• Add multi main func examples using go:build ignore by @devlights in #607
• Add singleapp/xml_shiftjis by @devlights in #608
• Add signal.Ignore() example by @devlights in #609
• Add signal.Reset() example by @devlights in #610
• Update examples/signal examples by @devlights in #611
• Update README, Taskfile, Gitpod config file by @devlights in #612
• Add TOML read/write examples by @devlights in #613
• Add runtime.Caller() example by @devlights in #614
• Add runtime.Callers example by @devlights in #615
• Add examples/basic/ioop/limitread.go by @devlights in #616
• Add examples/basic/ioop/onebyteread.go by @devlights in #617
• Update gomy version to v0.5.7 by @devlights in #618
• Add examples/socket example by @devlights in #619
• Update tcp 02 example by @devlights in #620
• Add convert slice to array example by @devlights in #621
• Add examples/singleapp/option_pattern by @devlights in #622
• Remove Makefile by @devlights in #623
• Update example by @devlights in #624
• Add joinhostport.go by @devlights in #625
• Add splithostport.go by @devlights in #626
• Add net.LookupPort() example by @devlights in #627
• Add padding arbitary length example by @devlights in #628
• Add examples/socket/tcp_03_dial_with_context by @devlights in #629
• Add context_and_timeafterfunc.go by @devlights in #630
• Add examples by @devlights in #631
• Add example by @devlights in #632
• Add range_loop_tmp_value_with_array.go by @devlights in #633
• Update Gitpod config by @devlights in #634
• Update go version to 1.20 by @devlights in #635
• Add context.WithCancelCause example by @devlights in #636

Full Changelog: v0.4.5...v0.5.0