Update golang.md

[rssnyder]

The current go plugin example code does not work out of the box with go 1.19:

➜  drone-plugin-go git:(main) ✗ GOOS=linux GOARCH=amd64 CGO_ENABLED=0 go build -o webhook
# github.com/rssnyder/drone-plugin-go
./plugin.go:9:11: undefined: strings
./plugin.go:10:8: undefined: os.GetEnv
./plugin.go:13:3: req declared but not used
./plugin.go:14:8: undefined: os.GetEnv
./plugin.go:15:8: undefined: os.GetEnv

• GetEnv->Getenv
• import strings
• use blank identifier
• ran go fmt

➜  drone-plugin-go git:(main) ✗ GOOS=linux GOARCH=amd64 CGO_ENABLED=0 go build -o webhook
➜  drone-plugin-go git:(main) ✗ go fmt
plugin.go

[d1wilko]

LGTM