inspired by temporalio/samples-go/searchattributes

1. Run a temporal service

   temporal server start-dev
2. In a different shell, register custom search attributes and run the example worker

   temporal operator search-attribute create --name CustomDatetimeField --type Datetime
   temporal operator search-attribute create --name CustomKeywordField --type Keyword
   temporal operator search-attribute create --name CustomTextField --type Text
   temporal operator search-attribute create --name CustomIntField --type Int
   temporal operator search-attribute create --name CustomDoubleField --type Double
   temporal operator search-attribute create --name CustomBoolField --type Bool
   go run examples/searchattributes/main.go worker
3. In a different shell, execute the workflow

   go run examples/searchattributes/main.go search-attributes \
       --custom-datetime-field=2024-01-01T00:00:00Z \
       --custom-keyword-field=foo-bar \
       --custom-text-field=foo-bar \
       --custom-int-field=42 \
       --custom-double-field=42 \
       --custom-bool-field=true