Remove update workflow and related tasks

Deno officially provides 'update' functionality, so we can remove our
custom tasks.

Author: lambdalisue

.github/workflows/update.yml

@@ -97,9 +97,6 @@
     "test": "deno test -A --parallel --shuffle",
     "test:coverage": "deno task test --coverage=.coverage",
     "coverage": "deno coverage .coverage",
-    "update": "deno run --allow-env --allow-read --allow-write --allow-run=git,deno --allow-net=deno.land,jsr.io,registry.npmjs.org jsr:@molt/cli deno.jsonc **/*.ts",
-    "update:write": "deno task -q update --write",
-    "update:commit": "deno task -q update --commit --prefix :package: --pre-commit=fmt,lint",
     "gen:function": "deno run -A ./.scripts/gen-function/gen-function.ts",
     "gen:option": "deno run -A ./.scripts/gen-option/gen-option.ts",
     "gen": "deno task gen:function && deno task gen:option && deno fmt",