try to support esm

[Yang-33]

I'm not sure

• CJS works as it is
• exports: { .. } is right
• tsconfig.esm.json is right
• CJS's package.json is right (other repository setup another package.json)
• ESM's package.json is right (same reason as above)
• how to remove const pkg = require("../package.json"); from http-(fetch|axios).ts

[Yang-33]

mochaを動かそうとすると、CJSを指定してもESMで動いてしまう用になってしまっている。それをなんとかして直せば次に進める