docs(readme): update hono/tiny size

[ryuapp]

Hono have grown.
I checked the size of hono/tiny with following the command.

npx esbuild --outdir=dist --bundle --minify ./src/preset/tiny.ts

Result

npx esbuild --outdir=dist --bundle --minify ./src/preset/tiny.ts

  dist\tiny.js  13.9kb

⚡ Done in 12ms

Based on the above result, I update the size in readme.
Minimal app may exceed 14kb.

Author should do the followings, if applicable

• Add tests
• Run tests
• yarn denoify to generate files for Deno

[yusukebe]

@ryuapp

You are right! Thanks, I'll merge it now.