Migrate to C3

[syumai]

C3 now has --template option. We should use this instead of gonew command.
https://developers.cloudflare.com/pages/get-started/c3/

[syumai]

Japanese article related to this: https://qiita.com/syumai/items/4fa73326357ed4313b50

[syumai]

some templates have been migrated: #157

• go-worker
• tinygo-worker